The only "condition" for our salvation is Jesus Christ on the cross whose blood was shed for His sheep.
I always hope RCs read their Bibles to know context as well as a verse.
The Holy Spirit is spirit; the water of regeneration is spirit. We are spiritually-reborn.
Just like Jesus is the "bread from heaven," but He is not a loaf of Wonderbread in the sky. He is our spiritual sustenance.
Our baptism is by the Holy Spirit who employs water as a sign and symbol of our status as His adopted children. The water does not save anyone. God alone by the regeneration of the Holy Spirit saves the fallen sinner. Take your eyes off the material word and raise them to the spiritual world. That's where salvation resides.
Nicodemus was having trouble understanding how a man could be "born again" when he is already old. John explained it isn't another earthly, human birth, but a spiritual rebirth. Spiritually, not materialistically.
Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God. That which is born of the flesh is flesh; and that which is born of the Spirit is spirit. Marvel not that I said unto thee, Ye must be born again. The wind bloweth where it listeth, and thou hearest the sound thereof, but canst not tell whence it cometh, and whither it goeth: so is every one that is born of the Spirit. Nicodemus answered and said unto him, How can these things be? Jesus answered and said unto him, Art thou a master of Israel, and knowest not these things? Verily, verily, I say unto thee, We speak that we do know, and testify that we have seen; and ye receive not our witness. If I have told you earthly things, and ye believe not, how shall ye believe, if I tell you of heavenly things?" -- John 3:4-12 "Nicodemus saith unto him, How can a man be born when he is old? can he enter the second time into his mother's womb, and be born?
John chastised Nicodemus for not understanding the spiritual truth of a believer's rebirth and his new life in Christ.
John continually stresses that while he is baptizing with water, it is merely a symbol of the heavenly baptism God bestows on His own.
He must increase, but I must decrease. He that cometh from above is above all: he that is of the earth is earthly, and speaketh of the earth: he that cometh from heaven is above all. And what he hath seen and heard, that he testifieth; and no man receiveth his testimony. He that hath received his testimony hath set to his seal that God is true. For he whom God hath sent speaketh the words of God: for God giveth not the Spirit by measure unto him. The Father loveth the Son, and hath given all things into his hand. He that believeth on the Son hath everlasting life: and he that believeth not the Son shall not see life; but the wrath of God abideth on him." -- John 3:27,30-36"John answered and said, A man can receive nothing, except it be given him from heaven...
The gift of faith in the Son is what saves us; faith alone through grace alone in Christ alone.
"In the last day, that great day of the feast, Jesus stood and cried, saying, If any man thirst, let him come unto me, and drink. He that believeth on me, as the scripture hath said, out of his belly shall flow rivers of living water." -- John 7:37-38"And Jesus said unto them, I am the bread of life: he that cometh to me shall never hunger; and he that believeth on me shall never thirst." -- John 6:35
Spiritual waters, spiritually-discerned.
Why "only"? Unless you are born of water in the spirit, you cannot inherit the Kingdom. Seems to me to be a condition.
Our baptism is by the Holy Spirit who employs water as a sign and symbol of our status as His adopted children. The water does not save anyone. God alone by the regeneration of the Holy Spirit saves the fallen sinner. Take your eyes off the material word and raise them to the spiritual world. That's where salvation resides.
Ah, but not merely a sign and symbol! The Holy Spirit employs water as an external sign and symbol of an internal/spiritual regeneration.
Of course water itself does not save anyone. Of course the regeneration of the Holy Spirit is what saves. But what John is saying here is that they go together. Water *and* the Spirit. Sacramental theology 101. :)