Luke records a parable of Jesus in Luke 18:9-17:
[Jesus] also told this parable to some who trusted in themselves that they were righteous, and treated others with contempt:
“Two men went up into the temple to pray, one a Pharisee and the other a tax collector. The Pharisee, standing by himself, prayed thus: ‘God, I thank you that I am not like other men, extortioners, unjust, adulterers, or even like this tax collector. I fast twice a week; I give tithes of all that I get.’
But the tax collector, standing far off, would not even lift up his eyes to heaven, but beat his breast, saying, ‘God, be merciful to me, a sinner!’
I tell you, this man went down to his house justified, rather than the other. For everyone who exalts himself will be humbled, but the one who humbles himself will be exalted.”
Now they were bringing even infants to him that he might touch them. And when the disciples saw it, they rebuked them.
But Jesus called them to him, saying, “Let the children come to me, and do not hinder them, for to such belongs the kingdom of God. Truly, I say to you, whoever does not receive the kingdom of God like a child shall not enter it.”
The parable and the event with the children which immediately follows are closely connected. The Pharisees thought that they were self-righteous. That is to say, they thought that they were justified before God on the basis of their works, such as the good things they’ve done or the fact that they followed all the “rules.” They therefore looked down on those who they thought weren’t as “good” as them, such as the tax collector (a convenient catch-all in the Gospels for “sinners”) in the parable.
The point of Jesus’ parable is to contrast these self-righteous individuals with the humble person who knows that he is a sinner and looks to God’s grace and mercy for justification. The self-righteous who trust in their own works cannot justify themselves before God. Justification only comes through God’s grace on account of Jesus Christ, a grace received through faith. Salvation does not depend on works, but rather on God’s grace and mercy (Ephesians 2:8-9). It is a gift.
The event with the infants and children illustrates this. Jesus’ disciples attempt to prevent the children from coming to Jesus. They seem to be thinking that it is not right for the children to come to him. But, Jesus intervenes and points out that not only should the children be allowed to come to him, but that all people need to become as children in order to receive salvation.
A young child knows how to receive gifts. They don’t try to work or earn their presents. They simply receive the things given to them as the gracious gifts they are. They rely on their parents’ grace for all that they have.
Adults, however, tend to believe that we must work for everything, and that good things come to us as rewards for the work we’ve done. Certainly, this is the way things tend to work in this world in our relationships with other people. For example, if we do good at work, then we tend to get promotions and raises. Therefore, we can have a hard time accepting gifts, believing them to be “charity” or somehow beneath our dignity to receive.
However, we cannot work for our salvation. Things work differently with respect to our relationship with God. The kingdom (or reign) of God comes to us on account of God’s grace; it is a gift given to us on account of what Jesus Christ has done for us through his death and resurrection. It is Jesus who worked for us, so the reign of God comes to us by God’s grace due to Jesus’ work, not ours. Thus, we simply receive salvation as the gift of God that it is.
Faith is simply taking God at His Word and believing Him when He tells us that this gift is really free and is really for us. Faith is also akin to becoming as a child before God, receiving His grace as the gift that it is, not trying to earn it, not trying to justify ourselves, not trusting in our own works – just receiving the gift and thanking God. God gives, we receive, and then we respond in faith, praise, and thanksgiving: like a child who opens a prized gift on Christmas morning.
(Image “Lasset die Kindlein zu mir kommen” – “Let the children come to me” – by Bernhard Plockhorst – http://www.cts.edu/ImageLibrary/Images/newwed/plokkids.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=1570303 )