John Wesley on Acts 16:28

But Paul cried - As they were all then in the dark, it is not easy to say, how Paul knew of the jailer's purpose; unless it were by some immediate notice from God, which is by no means incredible. With a loud voice - Through earnestness, and because he was at some distance. Do thyself no harm - Although the Christian faith opens the prospect into another life, yet it absolutely forbids and effectually prevents a man's discharging himself from this.