John Gill Commentary Exodus 14:15

"And Jehovah said unto Moses, Wherefore criest thou unto me? speak unto the children of Israel, that they go forward." — Exodus 14:15 (ASV)

And the Lord said unto Moses, why do you cry to me ?
&c.] The Targum of Jonathan is,

``why do you stand and pray before me?''

and no doubt this crying is to be understood of prayer, of mental prayer, of secret ejaculations put up by Moses to the Lord without a voice, for no mention is made of any: this shows, that though Moses most firmly believed that God would work salvation for them, yet he did not neglect the use of means, prayer to God for it; nor was the Lord displeased with him on that account, only he had other work for him to do, and he had no need to pray any longer, God had heard him, and would save him and his people:

speak unto the children of Israel, that they go forward ;
a little further, as Aben Ezra observes, until they were come to the sea shore, near to which they now were; and thither they were to move in an orderly composed manner, as unconcerned and fearless of their enemies.