Exodus 14

Exodus 14:4 I will harden Pharaoh’s heart… and I will be honoured upon Pharaoh
The Lord can bless; the Lord can curse.  He can soften our hearts; he can harden our hearts, but the Joseph Smith Translation says he didn't harden Pharaoh's heart.  
Joseph Fielding Smith
The Lord does not harden the hearts of men, they harden their own hearts.  In the scriptures where it says the Lord hardened Pharaoh's heart, it is a mistranslation in every case. (Answers to Gospel Questions, vol. 3, 136)
Exodus 14:9 the Egyptians pursued after them… and overtook them encamping by the sea
Now when the Egyptians had overtaken the Hebrews, they prepared to fight them, and by their multitude they drove them into a narrow place; for the number that pursued after them was six hundred chariots, with fifty thousand horsemen, and two hundred thousand foot-men, all armed. They also seized on the passages by which they imagined the Hebrews might fly, shutting them up between inaccessible precipices and the sea; for there was [on each side] a [ridge of] mountains that terminated at the sea, which were impassable by reason of their roughness, and obstructed their flight; wherefore they there pressed upon the Hebrews with their army, where [the ridges of] the mountains were closed with the sea; which army they placed at the chops of the mountains, that so they might deprive them of any passage into the plain. (Josephus, Antiquities of the Jews, Book II, 15:3)
Spencer W. Kimball
Hope must have long since died in the breasts of the timid Israelitish souls who knew not faith. Deserts and wilderness and the sea—the uncrossable sea! No boats, no rafts, nor time to construct them! Hopelessness, fear, despair must have gripped their hearts, and then the miracle came. It was born of the faith of their indomitable leader. A cloud hid them from the view of their enemies. A strong east wind blew all the night; the waters were parted; the bed of the sea was dry; and Israel crossed to another world and saw the returning sea envelop and destroy their pursuers. Israel was safe. Faith had been rewarded, and Moses was vindicated. The impossible had happened. An almost superhuman faith had given birth to an unaccountable and mysterious miracle that was to be the theme of the sermons and warnings of Israel and their prophets for centuries. (Conference Report, October 1952, Second Day—Morning Meeting 49)
George Q. Cannon
Israel fleeing before the hosts of Pharaoh, with the Red Sea in front and the armies of Pharaoh behind, was not a more threatening prospect than the Latter-day Saints have witnessed many times in their career. Metaphorically speaking, we have had the sea in front, we have had the armies in the rear, and we have had mountains on either side, and there has seemed to be no escape for us. But God by His wonderful power, has interposed and has delivered us; and we have emerged from our trials and from these seemingly inextricable difficulties stronger and more famous, and with greater faith than when we entered upon them. (Brian H. Stuy, ed., Collected Discourses, 5 vol. 1, July 21, 1889)
Exodus 14:11 Because there were no graves in Egypt, hast thou taken us away to die in the wilderness?
If we give the Israelites the benefit of the doubt, they had seen Moses’ miracles come as what appeared to be natural disasters, but they had not seen God fight an army for them.  The sight of the Egyptian army must have been terribly frightening and honestly, they didn’t know what the Lord would do.
If we don’t give the Israelites the benefit of the doubt, they have barely left Egypt and are already complaining.  This is the first of many murmurs.  Josephus wrote, “So they laid the blame on Moses, and forgot all the signs that had been wrought by God for the recovery of their freedom; and this so far, that their incredulity prompted them to throw stones at the prophet, while he encouraged them and promised them deliverance.” (Antiquities of the Jews, Book II, 15:4) The theme persists for 40 years, “why have you brought us out here?  Just so we could die in the wilderness?”  Like whining children, both Moses and the Lord weary with their shrill voices of faithlessness.  Eventually, they would do just that—they would die in the wilderness because they were not worthy to inherit the promised land.
John Taylor
They were not prepared to come into the presence of the Lord; they were not sufficiently pure, neither did they understand the laws and principles which God had communicated. But they murmured and murmured and that continually—the same as we do, we see something of the same spirit, we are found sometimes murmuring against God, or at least against some of the revelations he has given unto us, or against the priesthood, and in many instances without cause. (Journal of Discourses, 26 vols. [London: Latter-day Saints' Book Depot, 1854-1886], 21: 247 - 249)
Exodus 14:14 the Lord shall fight for you, and ye shall hold your peace
[Moses responds to the complaining multitude]  “It… is no better than madness, at this time to despair of the providence of God, by whose power all those things have been performed he promised, when you expected no such things… Nay, when we are in the utmost distress, as you see we ought rather to hope that God will succor us, by whose operation it is that we are now this narrow place, that he may out of such difficulties as are otherwise insurmountable and out of which neither you nor your enemies expect you can be delivered, and may at once demonstrate his own power and his providence over us. Nor does God use to give his help in small difficulties to those whom he favors, but in such cases where no one can see how any hope in man can better their condition. Depend, therefore, upon such a Protector as is able to make small things great, and to show that this mighty force against you is nothing but weakness, and be not affrighted at the Egyptian army, nor do you despair of being preserved, because the sea before, and the mountains behind, afford you no opportunity for flying, for even these mountains, if God so please, may be made plain ground for you, and the sea become dry land. (Antiquities of the Jews, Book II, 15:5)
Spencer W. Kimball
We forget that if we are righteous the Lord will either not suffer our enemies to come upon us—and this is the special promise to the inhabitants of the land of the Americas (see 2 Ne. 1:7)—or he will fight our battles for us (Ex. 14:14; D&C 98:37, to name only two references of many). This he is able to do, for as he said at the time of his betrayal, “Thinkest thou that I cannot now pray to my Father, and he shall presently give me more than twelve legions of angels?” (Matt. 26:53.) We can imagine what fearsome soldiers they would be. King Jehoshaphat and his people were delivered by such a troop (see 2 Chr. 20), and when Elisha’s life was threatened, he comforted his servant by saying, “Fear not: for they that be with us are more than they that be with them” (2 Kgs. 6:16). The Lord then opened the eyes of the servant, “And he saw: and, behold, the mountain was full of horses and chariots of fire round about Elisha.” (2 Kgs. 6:17.)
Enoch, too, was a man of great faith who would not be distracted from his duties by the enemy: “And so great was the faith of Enoch, that he led the people of God, and their enemies came to battle against them; and he spake the word of the Lord, and the earth trembled, and the mountains fled, even according to his command; and the rivers of water were turned out of their course; and the roar of the lions was heard out of the wilderness; and all nations feared greatly, so powerful was the word of Enoch.” (Moses 7:13.)
What are we to fear when the Lord is with us? Can we not take the Lord at his word and exercise a particle of faith in him? Our assignment is affirmative: to forsake the things of the world as ends in themselves; to leave off idolatry and press forward in faith; to carry the gospel to our enemies, that they might no longer be our enemies. (“The False Gods We Worship,” Ensign, June 1976, 6)
Exodus 14:19-20 the angel of God… went before the camp of Israel… between the camp of the Egyptians and the camp of Israel
The “angel of God” in this verse could be translated, “the Spirit of God,” and means the pre-mortal Spirit of Jehovah. The Lord had promised Moses, “I am come down to deliver them out of the hand of the Egyptians, and to bring them up out of that land unto a good land” (Ex. 4:8).  Now maybe you think the Lord himself didn’t do it, but sent another destroying angel down, but later verses suggest God took care of the Egyptians Himself, “Ye have seen what I did unto the Egyptians” (Ex. 19:4, italics added) and “the Lord looked unto the host of the Egyptians through the pillar of fire and of the cloud, and troubled the host of the Egyptians” (Ex 14:24, see also Ex. 33:12-17).
I am the Lord your God, even the God of your fathers, the God of Abraham and of Isaac and of Jacob.
I am he who led the children of Israel out of the land of Egypt; and my arm is stretched out in the last days, to save my people Israel. (D&C 136:21-22)
Exodus 14:21 the Lord caused the sea to go back by a strong east wind all that night
To some degree, verses 21 and 22 are contradictory.  The skeptics have considered the possibility that a strong wind, divine or not, could have blown the waters sufficiently to make a path for the Israelites to cross.  This of course is only possible if the water was sufficiently shallow, while still others have suggested locations for this exact phenomenon.  Is that how it happened?  The next verse said the water stood up like it was being held up by invisible walls, “the waters were a wall unto them on their right hand and on their left.”  Now maybe both occurred.  The Lord could have commanded the waters to defy gravity and form walls on each side, and then the wind could have been helpful to dry out the sea bed.  Otherwise, the boggy sea floor would have been unpassable.
Various theories have been postulated.  There is no reason to demand a scientific explanation.  If God wants water to defy gravity, I am sure he can do it.  A reasonable explanation with some useful geographic postulates is located at https://www.washingtonpost.com/news/wonk/wp/2014/12/08/no-really-there-is-a-scientific-explanation-for-the-parting-of-the-red-sea-in-exodus
Exodus 14:22 Moses stretched out his hand over the sea; and the Lord caused the sea to go back
Exodus 14:27 the Lord overthrew the Egyptians in the midst of the sea
As soon, therefore, as ever the whole Egyptian army was within it, the sea flowed to its own place, and came down with a torrent raised by storms of wind, and encompassed the Egyptians. Showers of rain also came down from the sky, and dreadful thunders and lightning, with flashes of fire. Thunderbolts also were darted upon them. Nor was there any thing which used to be sent by God upon men, as indications of his wrath, which did not happen at this time, for a dark and dismal night oppressed them. And thus did all these men perish, so that there was not one man left to be a messenger of this calamity to the rest of the Egyptians. (Antiquities of the Jews, Book II, 16:3)
Exodus 14:30 the Lord saved Israel that day out of the hands of the Egyptians
Now there must be a lesson to learn here—a type, a shadow, a metaphor?  How many times and how many ways does the Lord save Israel?  In the Old Testament, we find the phrase, “the Lord saved Israel that day” only twice:  in this instance and in 1 Sam. 14:23.  Yet, on a daily basis He saves Israel from wickedness. Doesn’t he save us from spiritual destruction as well as physical destruction?  Doesn’t he save us from the sins of Babylon and Egypt?
Another question to ask is, “Would God part the waters of the Red Sea for me?”  It is so easy to read these stories and view them as fantastic accounts completely irrelevant to our day.  But God is still God, and he still saves Israel from destruction.  So we must ask ourselves the question:  “Do I belong to the house of Israel?  Am I following the Prophet?  Have I done everything I can do?  Do I have the faith that God can work a miracle for me?”  If the answer to those questions is yes, then “Fear ye not, stand still, and see the salvation of the Lord.” (v. 13)
Another modern application can be seen in baptismal symbolism—that the Israelites were saved by water and by fire—the waters of the Red Sea and the pillar of fire which protected them. 
Gerald N. Lund
Being baptized of water is not sufficient to save a person; he must also receive the Holy Ghost, whose influence and presence are symbolized, among other things, by fire and burning. (See, for example, Acts 2:3-4; D&C 9:8-9.) Receiving the Holy Ghost after baptism is likened to being baptized by fire. (See Matt. 3:11; 2 Ne. 31:17.) As part of their deliverance from the slavery of Egypt, the Israelites were saved both by passing through water and by being overshadowed by fire. (Jesus Christ, Key to the Plan of Salvation [Salt Lake City: Deseret Book Co., 1991], 71 - 72)