Kids are not the church of tomorrow; they are part of the church of today. You do not have to grow up to serve the Lord. Kids in the Bible didn’t grow up first. Many served the Lord effectively BEFORE they ever grew up.
Josiah became king at eight years of age. Shortly after, he began to go through Israel smashing idols and leading a return to God. The nation turned around because one kid knew he didn’t have to grow up first. Josiah was not interested in becoming a future servant of God, he served God as a kid. The Bible calls him the best king Israel ever had.
A young servant girl walked up to rich, powerful Syrian commander Naaman and suggested that he travel to Israel where Elisha would minister healing to his leprosy on behalf of God. Naaman agreed and the rest is Biblical history. When Jesus launched His ministry in Luke 4 he referred to two Old Testament stories and one of them was the healing of Naaman. All of that happened because a little girl didn’t wait until she grew up to serve God.
Samuel, a young boy brought to the temple by his mother, heard God’s voice reveal the fate of Israel while Eli, the high priest, seemed oblivious to the danger Israel faced. A kid, not the high priest, heard God’s voice.
Could there have been anyone else in the crowd of over 5000 who brought lunch the day Jesus taught the vast group? A boy stepped up and offered his lunch in faith, enabling Jesus to multiply it to the mass of people. If the boy had waited to grow up first there would have been a lot of hungry people that day.
David slaying Goliath is the classic example. A shepherd boy takes on Goliath in front of the adults. When David was through, Goliath never bothered anyone again. Even though David stood on God’s covenant, faced a giant and won; he was still a kid.
Mary and Joseph found Jesus at twelve years of age in the temple “about His Father’s business.” That’s the objective: to bring kids to a place where they are “about their Father’s business” BEFORE they grow up.