And Moses said to the people, “Fear not, stand firm, and see the salvation of the Lord, which he will work for you today. For the Egyptians whom you see today, you shall never see again. The Lord will fight for you, and you have only to be silent.”
As Israel fled Egypt they had seen God already do the impossible. The miraculous plagues that Egypt endured and that Israel was spared displayed God's power and protection in supernatural ways. Moses led the people out of slavery and the Egyptians handed over their finest possessions to their former slaves. It had all been pretty amazing... that is until...
Pharaoh had one of his unpredictable changes of heart and gathered up his army. He pursued Israel with the intention of dragging them all back into slavery. Cornered at the Red Sea with God's pillar of fire blocking Pharaoh's marauders, Israel was afraid and complained to Moses. And the faith-filled answer of God's leader shows the courage Moses had to trust God in the next impossible circumstance.
Moses knew God would save His people. Moses knew Israel would never be enslaved in Egypt again. Deliverance would be worked. God would fight for His people and in faith Moses knew that just like the during the plagues, Israel would watch God work and they would just remain still. And his faith-filled answer back to a faithless nation would instruct Israel on the ways of God.
In that faith, Moses did what God said to do. He stretched his staff over the Red Sea and God parted the water and dried the sea bed. Israel walked across on dry land, and the pursuing Egyptians later drowned in the same sea. God would be glorified in the deliverance of His people once again. Faith kept silent and obeyed. God did all the work.