Matthew 5:47
"And if ye salute your brethren only, what do ye more than others? do not even the publicans so?"
Cross References (ranked by relevance)
Luke 6:32
For if ye love them which love you, what thank have ye? for sinners also love those that love them.
Matthew 5:20
For I say unto you, That except your righteousness shall exceed the righteousness of the scribes and Pharisees, ye shall in no case enter into the kingdom of heaven.
1 Peter 2:20
For what glory is it, if, when ye be buffeted for your faults, ye shall take it patiently? but if, when ye do well, and suffer for it, ye take it patiently, this is acceptable with God.