Like father, like son
It stands to reason that if God, as recorded in the Old Testament, was so intensely opposed to complaining, then we might expect His Son, Jesus Christ, to be equally serious about it in the New Testament. After all, Jesus said, "He that hath seen me hath seen the Father" (John 14:9). Like Father, like Son.
Sure enough, the New Testament indicates that Jesus was every bit as intolerant of complaining as was His Father in the Old Testament. In fact, Jesus repeatedly sets Himself against one of the most menacing types of complaining-people complaining about other people. And Jesus responds the same way every time.
Jesus and the "complainiacs"
Jesus actually fielded complaints against five different types of people: the fortunate, the insensitive, the unspiritual, the outsider, and the wicked. When all the complaint stories are studied together, several truths emerge about how Jesus handled complaints about other people: (1) Jesus never gave the complainer the satisfaction he was looking for; (2) Jesus never allowed the complainer to persist in his complaining; (3) Jesus never tolerated an excessive ripping apart of the character of another person, even the ungodly; (4) Jesus often turned the tables and offered a penetrating insight about the complainer's own heart; and (5) Jesus sometimes even issued a spiritual warning to the complainer himself.
Essentially, Jesus responded to every person's complaint about other people with a simple and sobering rebuke: Complaint denied!
The story of the heir and his brother in Luke 12:13-21is a case in point. In this story a man complains to Jesus about his brother's failure to divide the inheritance with him. Jesus responds by stating that His own sacred mission does not involve being wedged into the middle of such disputes.