Charles Spurgeon Commentary Exodus 14:13-15

"And Moses said unto the people, Fear ye not, stand still, and see the salvation of Jehovah, which he will work for you to-day: for the Egyptians whom ye have seen to-day, ye shall see them again no more for ever. Jehovah will fight for you, and ye shall hold your peace. And Jehovah said unto Moses, Wherefore criest thou unto me? speak unto the children of Israel, that they go forward." — Exodus 14:13-15 (ASV)

Moses was no doubt praying in his heart, though it is not recorded that he uttered any words in prayer; but it was not the time for prayer, it was the time for action.

When people who know their duty sometimes say, "We will make it a matter of prayer," they generally mean that they will try to find some excuse for not doing it. You need not pray about any matter when you know what you ought to do; go and do it.