a mote in someone's eye

a mote in someone's eye

a trivial fault in someone which is less serious than one in someone else who is being critical.
A mote is a tiny speck of dust or a similar substance. The phrase comes from Matthew 7:3–5: ‘Why beholdest thou the mote that is in thy brother's eye, but considerest not the beam that is in thine own eye?’: the implication is that someone is ignoring a glaring fault of their own while criticizing a smaller one in someone else.
See also: eye, mote