The exercise of faith and then the public testimony of water baptism are what is required under the New Covenant after God has regenerated a person to spiritual life.
"Not by works of righteousness which we have done, but according to His mercy He saved us, by the washing of regeneration and renewing of the Holy Ghost." (Titus 3:5). This is not the external washing in any kind of baptistry pool which saves us. It's the washing done by the Spirit internally.
Christian baptism is an outward sign of the inward action of grace, or merits of Christ’s passion blood and death applied to our souls!
We cannot see the inward action of grace purifying the soul, so God gave us the outward “sign” of water washing the body to indicate the inward action of grace and connected the two.
Heb 10:22
Let us draw near with a true heart in full assurance of faith, having our hearts sprinkled from an evil conscience, and our bodies washed with pure water.
1 Jn 2:20 But ye have an unction from the Holy One, and ye know all things.
1 Jn 2:27 But the anointing which ye have received of him abideth in you, and ye need not that any man teach you: but as the same anointing teacheth you of all things, and is truth, and is no lie, and even as it hath taught you, ye shall abide in him.
(Born of God) faith and baptism
Jn 1:12-13 But as many as received him, to them gave he power to become the sons of God, even to them that believe on his name:
13 Which were born, not of blood, nor of the will of the flesh, nor of the will of man, but of God.
1 Jn 5:4 For whatsoever is born of God overcometh the world: and this is the victory that overcometh the world, even our faith.
5 Who is he that overcometh the world, but he that believeth that Jesus is the Son of God?
6 This is he that came by water and blood, even Jesus Christ; not by water only, but by water and blood. And it is the Spirit that beareth witness, because the Spirit is truth.
7 For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one.
8 And there are three that bear witness in earth, the Spirit, and the water, and the blood: and these three agree in one.
Born of God by baptism
1 pet 1:2 Elect according to the foreknowledge of God the Father, through sanctification of the Spirit, unto obedience and sprinkling of the blood of Jesus Christ: Grace unto you, and peace, be multiplied.
1 Peter 1:22
Seeing ye have purified your souls in obeying the truth through the Spirit unto unfeigned love of the brethren, see that ye love one another with a pure heart fervently: see Ez 36
Rev 1:5 And from Jesus Christ, who is the faithful witness, and the first begotten of the dead, and the prince of the kings of the earth. Unto him that loved us, and washed us from our sins in his own blood, (baptism rom 6:3-4)