When God redeemed Israel from bondage in Egypt, he led them to freedom toward a new home. However, they were rebellious and stubborn and initially refused to enter the land, opting to elect a new leader and return to Egypt. As a result, God told them this:
“How long will this wicked community grumble against me? I have heard the complaints of these grumbling Israelites. So tell them, ‘As surely as I live, declares the Lord, I will do to you the very thing I heard you say: In this wilderness your bodies will fall—every one of you twenty years old or more who was counted in the census and who has grumbled against me. Not one of you will enter the land I swore with uplifted hand to make your home, except Caleb son of Jephunneh and Joshua son of Nun. As for your children that you said would be taken as plunder, I will bring them in to enjoy the land you have rejected. But as for you, your bodies will fall in this wilderness. Your children will be shepherds here for forty years, suffering for your unfaithfulness, until the last of your bodies lies in the wilderness. For forty years—one year for each of the forty days you explored the land—you will suffer for your sins and know what it is like to have me against you.’ I, the Lord, have spoken, and I will surely do these things to this whole wicked community, which has banded together against me. They will meet their end in this wilderness; here they will die" ( Numb 14:27-35).
The children under 20 years old would suffer for the sins of their fathers by being stuck living in the wilderness for forty years. However, God does not hold those under twenty years responsible in the same way he does those who are twenty and older. Those under twenty would enter the land after their parents had all died in the wilderness.
In Deuteronomy, those who were under twenty are now adults and their parents have all died in the wilderness. Moses is preparing them to enter the land God granted to them. Moses recounted their history, and how their parents had rebelled against God, refusing to enter the land, making plans to return to Egypt. Then Moses reminded them of what God had said:
"When the Lord heard what you said, he was angry and solemnly swore: 'No one from this evil generation shall see the good land I swore to give your ancestors, except Caleb son of Jephunneh. He will see it, and I will give him and his descendants the land he set his feet on, because he followed the Lord wholeheartedly.'
Because of you the Lord became angry with me also and said, 'You shall not enter it, either. But your assistant, Joshua son of Nun, will enter it. Encourage him, because he will lead Israel to inherit it. And the little ones that you said would be taken captive, your children who do not yet know good from bad—they will enter the land. I will give it to them and they will take possession of it" (Dt 1:34-39).
This text jumped out at me: " And the little ones that you said would be taken captive, your children who do not yet know good from bad—they will enter the land…" This group included everyone under twenty years old. God did not hold those who were under twenty responsible as an adult.
This reminds me of some of the scientific literature I have seen on human growth and development. Apparently, the brain is the last part of the human body to physically mature. Even though the rest of the body looks like an adult body, the brain is still developing until about age twenty. This is why a seventeen or eighteen year old might respond to a situation more on emotion and impulse rather than sound judgment. Perhaps this is why God does not hold them responsible as adults. They were not yet fully mature.
As I think about the implications this has for the conversion of children, I wonder about the wisdom in pushing teenagers to be baptized. If it is an adult decision, and if it is the most important decision one will make in life more than even marriage, then pushing a teen toward it may not be the best course of action. Expecting a life-long adult commitment, with adult understanding that requires an adult level of emotional maturity may be setting a teen up for failure and discouragement, not because he or she is not committed, but because he or she may not yet be emotionally capable of such a decision. This means that if a child wants to be baptized, a parent may hold them off for the same reason they would hold them off from getting married. One would not disfellowship a child for the same reason one would not try a juvenile in an adult court. The child is the responsibility of the parent until he or she begins to transition into adulthood. Childhood is a time of preparation, training, instruction, and encouragement.
As a practice, I do not discourage children who want to make that commitment. They love God and want to please him, which pleases God. They want to follow Jesus, which I encourage. However, it is a marriage, and I explain it in terms of marriage. It is a very adult decision. I have often thought about whether starting a tradition of a formal period of betrothal up till the day of baptism would be a good thing. This would involve instruction and guided growth in service and ministry. Something to act as a symbol of that betrothal might help to strengthen a child's faith and commitment. This might help with the child's desire to express his commitment to Christ even though he or she may not be emotionally or spiritually ready for baptism.
In the end, I suppose the encouragement for parents in this regard is to not get bent out of shape if a child is not yet beating down the doors to the baptistery yet. The more important thing is not so much whether they have been baptized, but whether parents are instructing them regularly, whether parents are including them in service and ministry in the name of Christ, and whether parents are modeling love for God and for the neighbor. I have known kids who were pushed toward baptism by parents, but they were never really committed. Baptism is not some magic ritual that equates to commitment.
I think of my own experience with my own children. I included them in ministry, service, and discussions about God, scripture, and service. I had not yet considered the age twenty marker that God identified in the text from my reading. My younger two children were older teens when they made the decision to be baptized. However, they had reached a level of emotional maturity that they understood the level of commitment this would take. They were what some people called, "an old soul." They have been involved and committed and are still faithful Christians today.