Charles Spurgeon Commentary Acts 16:23-25

"And when they had laid many stripes upon them, they cast them into prison, charging the jailor to keep them safely: who, having received such a charge, cast them into the inner prison, and made their feet fast in the stocks. But about midnight Paul and Silas were praying and singing hymns unto God, and the prisoners were listening to them;" — Acts 16:23-25 (ASV)

Another prayer-meeting, and a praise-meeting, too. There were only two persons at it; but they prayed, and sang praises unto God.