With him I speak mouth to mouth, Even openly, and not in dark sayings, And he beholds the form of the LORD. Why then were you not afraid To speak against My servant, against Moses? [Numbers 12:8]
In chapter 12 of the book of Numbers, Aaron and Miriam were displeased with Moses and they spoke against Moses. There was no record of how Moses responded. Some commentary writers, eg Matthew Henry, believed that the mention of Moses being a humble, or meek, man in verse 3 (Numbers 12:3) hinted that Moses did not defend himself against the criticism and he probably ignored them. Later the LORD defended Moses and punished Miriam. Probably she was the ringleader and Aaron was an accomplice.
This might be an example on handling criticism but it does not mean we cannot defend ourselves against criticism. For example, Paul defended his credentials and apostleship. The crux of the matter is trusting the LORD to settle it for us when faced with criticism.
Also, note that if the LORD punished Miriam for speaking against Moses, then what would happen to those who speak, or sin, against the Son of God?