And brought them out, and said, Sirs, what must I do to be saved? And they said, Believe on the Lord Jesus Christ, and thou shalt be saved, and thy house (Acts 16:30-31).
Matthew Henry on Acts 16:31:
The condition required: Believe in the Lord Jesus Christ. We must admit the record that God hath given in his gospel concerning his Son, and assent to it as faithful, and well worthy of all acceptation. We must approve the method God has taken of reconciling the world to himself by a Mediator; and accept of Christ as he is offered to us, and give up ourselves to be ruled and taught and saved by him. This is the only way and a sure way to salvation. No other way of salvation than by Christ, and no other way of our being saved by Christ than by believing in him; and no danger of coming short if we take this way, for it is the way that God has appointed, and he is faithful that has promised.