Flesh gives birth to flesh, but the Spirit gives birth to spirit.
That which is from the earthly can only give rise to the earthly and that which is of the spiritual can only come from a Spiritual source.
Rebirth is a recurring theme throughout the New Testament. (1Peter 1:3, 22-23; James 1:18; Titus 3:5; Rom 6:1-11; 1Cor 3:1-2; 2Cor 5:17; Gal 6:15; Eph 4:22-24; Heb 5:12-14)
1 Peter 1:3 Praise be to the God and Father of our Lord Jesus Christ! In his great mercy he has given us new birth into a living hope through the resurrection of Jesus Christ from the dead,
1 Peter 1:22-23 Now that you have purified yourselves by obeying the truth so that you have sincere love for your brothers, love one another deeply, from the heart. For you have been born again, not of perishable seed, but of imperishable, through the living and enduring word of God.
James 1:18 He chose to give us birth through the word of truth, that we might be a kind of firstfruits of all he created.
Titus 3:5 he saved us, not because of righteous things we had done, but because of his mercy. He saved us through the washing of rebirth and renewal by the Holy Spirit,