Christ tells us that to enter God’s kingdom we must receive it like a little child would. (Lk 18:17) Some manner of childlikeness is therefore intrinsic in regeneration, so it’s important to understand what this looks like: there’s no salvation without it.
Firstly, we note that God isn’t telling us to be childish (1Co 13:11), foolish (Pr 22:15), or childlike in our understanding (1Co 14:20a,c); God wants us to be mature in knowledge and wisdom. Rather, we’re to be as children in malice (vs 20b), not bitter, vengeful, jaded and resentful, wishing harm to others for the sake of it.
Neither are we to be voluntarily weak and vulnerable, inappropriately dependent on others. God commands us to be poor in spirit (Mt 5:3), not spiritually self-sufficient (2Co 3:5), but He also commands us to be strong (1Co 16:13)
Godly childlikeness seems to be primarily in the context of humility: small children don’t tend to think too highly of themselves. (Mt 18:4) They’re not preoccupied with status, with how they stack up against others, or in feeling certain tasks are beneath them. They aren’t envious or bitter.
Further, small children are generally very teachable, curious, wanting to learn, grow and understand. (1Pe 2:2) They tend to trust what adults tell them, depending on those who are older and wiser to guide and protect them. This isn’t the same as being gullible (Pr 14:15); children aren’t capable of understanding the world well enough to navigate it wisely (Lk 2:52), so they’re involuntarily dependent and vulnerable. (Mt 18:6) They aren’t locked into preconceived biases which blind them to the truth when they hear it. They are, in a sense, strong in faith. This is how we’re to respond to God, as a little child trusts a loving parent: God is infinitely beyond us in power and knowledge, so we should trust what He says implicitly, and without reservation.
Small children tend to repent when appropriately corrected, and to try to please those in authority when consistently and lovingly disciplined. Their hearts aren’t hard; they enjoy being loved and cared for, being in relationship with their father, being close to him and nurtured by him. Similarly, regeneration produces in us an obedient heart (1Pe 1:2), one that readily yields to correction and seeks to serve and obey our Heavenly Father.
Unless we’re transformed, and become as little children, we won’t enter His kingdom. (Mt 18:3) We must find God at work in us, transforming us in humility and holiness such that we’re unassuming, trusting in the goodness of our Father, not pretending to be worthy of the gift, simply joyful and grateful.