In the context, Christ's disciples were arguing over which one would be the greatest in the kingdom. An argument due to arrogance and pride. Jesus brings a child before them and tells them "except ye turn" ...meaning they would have to repent of this attitude to have a place in the kingdom. Then Jesus explains that they would have to take on certain traits that children have to enter the kingdom. Those disciples would have to become "
like" children.
These disciples would have to repent/change of their wrong in their arguing and become "like" children in humility. Therefore when Jesus speaks of "
these little that believe in Me" He is not referring to children age wise but refers to those disciples that have a child like faith, those that have humility in their heart. Those with humility will repent.
Even John Gill says of Mt 18:6"
"
But whoso shall offend one of these little ones,.... Not in age, but are little and mean in their own eyes, and contemptible in the esteem of the world; though otherwise men of great grace, gifts, and usefulness; who may be said to be offended, when they are not received; their persons despised, their ministry rejected, and they reproached and persecuted; and everything done to them to discourage, and cause them to stumble and fall, to drop their profession of Christ, to quit his service, and desert his cause: and that such persons are designed, appears by the following descriptive character of them,
which believe in me; which cannot be said of infants, or little ones in age, and who also are not capable of offence; but must be understood of adult persons, of such who by faith look unto, lay hold on, and receive the Lord Jesus Christ, as their Saviour and Redeemer, and who make a profession of their faith in him; and chiefly of such who preach the doctrine of faith, who having believed, therefore speak; and who are generally the butt of the contempt, reproach, and persecution of men."
Albert Barnes on Mt 18:6 "
These little ones - That is, Christians manifesting the spirit of little children, 1 John 2:1, 1 John 2:12, 1 John 2:18, 1 John 2:28."
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No child that was brought to Jesus did Jesus say those children have sin and commanded those children be baptize. No examples of disciples baptizing children. Jesus simple used various traits possessed by children and said His disciples should possess those same traits.