Acts 12:4-5

⁴Herod thought, “I will wait until the end of that ceremony, then I will judge Peter and kill him.” So they put Peter in jail, and Herod told 16 soldiers to guard him there. Those soldiers were in 4 little mobs, with 4 soldiers in each little mob.

⁵Peter stayed there in jail, and the other Christians prayed for him a lot.