Acts 16:31 says, “Believe on the Lord Jesus, and you shall be saved, you and your household.” Here Christ is revealed as the Lord Jesus. As such, He is the object of the believer’s faith for the salvation of the believer and his household. To believe in the gospel is mainly to believe in Jesus Christ. Furthermore, to believe is to believe on, to take the ground and stand on, the Lord Jesus to be saved. We believe not only into Christ but also on Christ. This is to take the ground and the standing on the person of Christ and all that He has accomplished, both of which constitute the belief, the faith, of God’s New Testament economy. We believe on Christ as the ground and standing so that we may be saved.
Furthermore, the word household in verse 31 indicates that the family of the believer is a complete unit for God’s salvation, like the family of Noah (Gen. 7:1), the families partaking of the Passover (Exo. 12:3-4), the family of the harlot Rahab (Josh. 2:18-19), the family of Zaccheus (Luke 19:9), the family of Cornelius (Acts 11:14), the family of Lydia (16:15), the family of the jailer in verse 31, and the family of Crispus in 18:8. Hence, Christ as the Lord Jesus is the object of the believer’s faith for the salvation not only of the believer but also of his household.
Christ is a man to judge the world, designated by God in righteousness, and proved by God’s raising Him from the dead.
In 17:30 and 31 Paul says, “Therefore, having overlooked the times of ignorance, God now charges all men everywhere to repent, because He has set a day in which He is to judge the world in righteousness by the man whom He has designated, having furnished proof to all by raising Him from the dead.” The day set by God for the judgment of the world will be the day when Christ will judge the living men from the throne of His glory before the millennium (Matt. 25:31-36). This probably does not include the day when He will judge dead men at the great white throne after the millennium (Rev. 20:11-15). According to Acts 10:42 Christ has been designated by God “to be the Judge of the living and the dead.” He will be the Judge of the dead after the millennium at the great white throne. Second Timothy 4:1 and 1 Peter 4:5 also say that Christ will judge both the living and the dead. The day in Acts 17:31 refers particularly to the day Christ will judge the living, because on this day He will judge “the world,” which should refer only to living men. This day of Christ’s judgment on earth will be brought in by His coming back. He was designated by God to execute this judgment, and God’s raising Him from the dead is strong proof of this. In their preaching to the Gentiles, both Peter in 10:42 and Paul here and in 24:25 stressed the coming judgment of God.
The Greek word rendered “proof” in 17:31 may also be translated “faith,” “assurance,” “guarantee.” The resurrection of Christ is proof and assurance of His coming back to judge all the inhabitants of the earth. This is guaranteed that we may have faith in it and that it may lead us to repent (v. 30).
Paul’s word regarding Christ as the man designated by God and regarding His resurrection indicates that Paul was fully constituted of this One and of His resurrection. Paul was led, guided, and directed absolutely by the Spirit of Jesus. Because he was constituted of the Spirit of Jesus, his goal, no matter what the subject in speaking, was to preach Christ and His resurrection.