“The angel of God who was going before the Israelite army moved and went behind them; and the pillar of cloud moved from in front of them and took its place behind them.” (Exodus 14:19)
We find the Israelites (having been transformed from the Hebrews during the leaving of Egypt) at the banks of the Red Sea with the Egyptian army chasing them down. I am not sure it is entirely accurate to say they were an “army”, unless that means it was a very large group of people with a great deal of possessions packed in wagons etc. In fact other translations use “camp” as opposed to “army”. Now the Egyptians, that was an army!