A man who knows that he is saved by believing in Christ does not, when he is baptized, lift his baptism into a saving ordinance. In fact, he is the very best protester against that mistake, because he holds that he has no right to be baptized until he is saved.
Author: Charles Spurgeon Source: Baptismal Regeneration, sermon 10.326.
After many painful trials, which none can know, but those who are taught to relinquish a system in which they had been educated, I settled down in the full persuasion, that the immersion of a professing believer in Christ is the only Christian baptism.
We ought to regard the sacrament of baptism with reverence. An ordinance of which the Lord Jesus Himself partook, is not to be lightly esteemed. An ordinance to which the great Head of the Church submitted, ought to be ever honorable in the eyes of professing Christians.
In Colossians 2:12 and 1 Peter 3:21 baptism is an expression of the faith of the person being baptized. I [do] not see how an infant could properly receive this ordinance as an expression of his or her faith.
Author: John Piper Source: Brothers, We Are Not Professionals, 2002, p. 131
I do not elevate the time or mode of baptism to a primary doctrine.
Author: John Piper Source: Brothers, We Are Not Professionals, 2002, p. 128
John's baptism...was a radical act of individual commitment to belong to the true people of God, based on personal confession and repentance... This is one of the main reasons that I do not believe in baptizing infants, who cannot make this personal commitment or confession or repentance. John's baptism was an assault on the very assumptions that give rise to much infant baptism.
Author: John Piper Source: Sermon: I Baptize You With Water, Matthew 3, May 4, 1997
God's people should be baptized because God commanded it, not because some church requires it.