Acts 16:33

He took them. As soon as conviction came to the jailer he gave evidence of a change of heart. The hardened pagan official became a sympathetic Christian, solicitous for the welfare of the suffering evangelists. He had no authority to release the prisoners, but he did what he could to ease their pains by washing their lacerated backs. Such tender ministry was practical proof of his conversion.

Was baptized. It is clear that the instruction given by Paul and Silas was comprehensive. It was wholeheartedly received by the jailer’s household, and led them to desire and to receive baptism. He who had just washed the wounds of his prisoners, was now, with those who were dear to him, washed from the stains of sin. This reciprocal ministry is typical of genuine Christian fellowship. It is not unreasonable to suppose that the prison contained a pool or cistern where baptism by immersion could take place. See on Matt. 3:6.

Straightway. No time was lost. Between midnight and dawn (vs. 25, 35) the prison had been shaken, the prisoners released, the vital question asked, the answer given, conversion experienced, and baptism administered.