Acts 16:27

And the keeper of the prison, awaking from sleep and seeing the prison doors open, supposing the prisoners had fled, drew his sword and was about to kill himself.

1. The jailer wakes up from his sleep. With the prisoners secured, the doors locked, and all the other guards in place, he was comfortable dozing off.

2. The earthquake, the open doors, the rattling chains, and the excitement of the prisoners causes him to awaken.

3. With chains off and doors open - it is natural to think that all have escaped. He knew that with all the prisoners gone, he would die. So he was ready to take his own life.