Albert Barnes Commentary John 3:5

"Jesus answered, Verily, verily, I say unto thee, Except one be born of water and the Spirit, he cannot enter into the kingdom of God!" — John 3:5 (ASV)

Be born of water. By water, here, is evidently signified baptism. Thus the word is used in Ephesians 5:26 and Titus 3:5. Baptism was practiced by the Jews in receiving a Gentile as a proselyte. It was practiced by John among the Jews, and Jesus here says that it is an ordinance of His religion, and the sign and seal of the renewing influences of His Spirit. So He said (Mark 16:16), He that believeth and is baptized shall be saved. It is clear from these places, and from the example of the apostles (Acts 2:38, 41; 8:12-13, 36-38; 9:18; 10:47-48; 16:15, 33; 18:8; 22:16; Galatians 3:27) that they considered this ordinance as binding on all who professed to love the Lord Jesus.

And though it cannot be said that no one who is not baptized can be saved, yet Jesus meant, undoubtedly, to be understood as affirming that this was to be the regular and uniform way of entering into His church; that it was the appropriate mode of making a profession of religion; and that one who neglected this, when the duty was made known, neglected a plain command of God.

It is clear, also, that any other command of God might as well be neglected or violated as this one, and that it is the duty of everyone not only to love the Savior, but to make an acknowledgment of that love by being baptized and by devoting oneself thus to His service.

But, lest Nicodemus should suppose that this was all that was meant, He added that it was necessary that he should be born of the Spirit also. This was predicted of the Savior, that He should baptize with the Holy Ghost and with fire (Matthew 3:11). By this is clearly intended that the heart must be changed by the agency of the Holy Spirit; that the love of sin must be abandoned; that one must repent of crime and turn to God; that one must renounce all one's evil propensities and give oneself to a life of prayer and holiness, of meekness, purity, and benevolence. This great change is in Scripture ascribed uniformly to the Holy Spirit (Titus 3:5; 1 Thessalonians 1:6; Romans 5:5; 1 Peter 1:22).

Cannot enter into. This is the way, the appropriate way, of entering into the kingdom of the Messiah here and hereafter. One cannot enter into the true church here, or into heaven in the world to come, except in connection with a change of heart and by the proper expression of that change in the ordinances appointed by the Savior.