Mark 9:33–37, 42, Matthew 18:1–5, and Luke 9:46–48 give parallel accounts of Jesus’ use of a child to illustrate His teaching to the disciples. These passages differ, however, in which teaching they choose to report. We see at least four teachings from these passages.
Have the faith and humility of a child (Matt 18:3–4). Speaking of how to “enter the kingdom of heaven,” Jesus says that we must “turn and become like children,” which means that one “humbles himself like this child,” that is, a child that Jesus had called to stand in their midst (Matt 18:3–4; cf. 18:1–2). We must humbly trust in Christ and not ourselves if we hope to enter His kingdom.
Welcome all believers alike with no thought to their social standing (Matt 18:5; Mark 9:36–37). Jesus speaks of one who “receives one such child in my name” as the one who “receives me” (Matt 18:5; Mark 9:37). The phrase “one such” implies that it was not only children that Jesus admonished His disciples to receive, but all who are like children in some sense. In context, this sense is along the lines of who is the greatest in the kingdom of heaven (Matt 18:1). Even if one is like a child (one without social standing and recognition), if such a one bears the name of Jesus (“receives…in my name”), then we as believers should seek to welcome and serve such a one, not figure out whether we are ranked higher than such a person in the coming kingdom of God. And, by serving all believers, and especially those who are little in the eyes of men, we are thereby evaluated by God to be the greatest in His kingdom (Matt 18:4; cf. also James 2:1–10).
To welcome all believers without discrimination is to welcome Jesus and, therefore, His Father (Matt 18:5; Mark 9:36–37; Luke 9:48). One of the primary ways we show our love for God is to show our love for His people. By welcoming those who bear His name, it is as if we were welcoming Jesus Himself (Matt 18:5; Mark 9:37a; Luke 9:48a), and to welcome Jesus is to welcome His Father, the One who sent Him on our behalf (Mark 9:37b; Luke 9:48b). How we treat others is a reflection of how we treat God Himself (cf. also Matt 25:31–46).
Causing a believing child to sin is great sin (Matt 18:6; Mark 9:42). If we allow our pride to dismiss other believers and provoke them to sin, we commit great sin ourselves (Matt 18:8; Mark 9:42; cf. 9:38–41). Rather, we should support one another and strive for unity instead of thinking that we alone our righteous in our ways (cf. also John 13:34–35 and Rom 15:7).