46 An argument started among the disciples as to which of them would be the greatest.
47 Jesus, knowing their thoughts, took a little child and had him stand beside him.
48 Then he said to them, "Whoever welcomes this little child in my name welcomes me; and whoever welcomes me welcomes the one who sent me. For he who is least among you all—he is the greatest."
We hear a lot about childlike faith, about needing to become like a little child to enter the kingdom of God. But I don't think that's necessarily what this passage is referring to. I think it's referring once again to Jesus' directive to love and serve others disinterestedly, without thinking about what we can get out of it.
Jesus says, "Whoever welcomes this little child in my name welcomes me." Most of the time, a little child can't give us anything, certainly not anything material. Little children demand a lot of our time -- they can't feed themselves, they can't take care of themselves, they're constantly asking questions. When our own kids demand this of us, we're usually ready to help -- after all, they're our flesh and blood, and it's in our own self-interest to see that they are cared for.
But what if we expand the idea of "this little child" to include other children in the community (who perhaps live in a single-parent home, and that parent maybe works extra shifts to keep food on the table, leaving the child deprived of parental attention); the homeless, who don't have anything beyond a backpack and sleeping bag to call their own, much less anything they could give us; the developmentally disabled, who can't take care of themselves like others of their physical age can; and the senior citizen living on a fixed retirement who can't work, and needs some extra help to make ends meet. Am I willing to give of my time and resources to serve these "little ones" that often get overlooked, without anyone but my heavenly Father noticing? Will I give to those who can't give anything back to me?
The world's system says, "Look out for yourself. Sure, go ahead and help others, just as long as there's something in it for you."
But Jesus, the King of the upside-down kingdom, where the least is the greatest, says, "Give without expecting anything in return. Go the second mile. Love your enemies." He calls us to sacrifice ourselves for others, just as He sacrificed Himself for us.