“Find that quote for me in the bible.”
I will assume you know that is not a quote. It is a definition.
Baptism is commanded of BELIEVERS - see Matthew 28:18-20.
How can it be a definition if it is not biblical???
Here’s a quote from the Barnabas, an early Christian who wrote this after the destruction of the Temple but probably before the Bar Kochba rebellion, roughly 70-130 AD
In Chapter 19 he writes:
“Thou shalt not slay the child by procuring abortion; nor, again, shalt thou destroy it after it is born. Thou shalt not withdraw thy hand from thy son, or from thy daughter, but from their infancy thou shalt teach them the fear of the Lord.(252)”
How does that strike you?
The following is part of a letter by Clement, probably that Clement mentioned by Paul in Philippians 4:3. He probably lived from about 30AD to as far as the end of that 1st century.
He writes:
“Let your children be partakers of true Christian training; let them learn of how great avail humility is with God-how much the spirit of pure affection can prevail with Him-how excellent and great His fear is, and how it saves all those who walk in(94) it with a pure mind. For He is a Searcher of the thoughts and desires [of the heart]: His breath is in us; and when He pleases, He will take it away. “
How does that strike you?
From Ignatius who lived from about 30 AD until 107 AD, martyred under Emperor Trajan. Ignatius writes to Christians in Philadelphia:
“Children, obey your parents, and have an affection for them, as workers together with God for your birth [into the world]. Servants, be subject to your masters in God, that ye may be the freed-men of Christ.(28) Husbands, love your wives, as fellow-servants of God, as your own body, as the partners of your life, and your co-adjutors in the procreation of children. Virgins, have Christ alone before your eyes, and His Father in your prayers, being enlightened by the Spirit. May I have pleasure in your purity, as that of Elijah, or as of Joshua the son of Nun, as of Melchizedek, or as of Elisha, as of Jeremiah, or as of John the Baptist, as of the beloved disciple, as of Timothy, as of Titus, as of Evodius, as of Clement, who departed this life in [perfect] chastity,(29) Not, however, that I blame the other blessed [saints] because they entered into the married state, of which I have just spoken.(30) For I pray that, being found worthy of God, I may be found at their feet in the kingdom, as at the feet of Abraham, and Isaac, and Jacob; as of Joseph, and Isaiah, and the rest of the prophets; as of Peter, and Paul, and the rest of the apostles, that were married men. For they entered into these marriages not for the sake of appetite, but out of regard for the propagation of mankind. Fathers, “bring up your children in the nurture and admonition of the Lord; “(31) and teach them the holy Scriptures, and also trades, that they may not indulge in idleness. Now [the Scripture] says, “A righteous father educates [his children] well; his heart shall rejoice in a wise son.”