В чужом глазу сучок велик

We notice other men's insignificant imperfections but are unaware of our own great ones. See Не видит сова, какова сама (H)

Var.: В чужом глазу и соринка видна, а в своём и бревна не видно

Cf: We see a mote in other men's eyes when there's a beam in our own (Br.). We see a mote in our brother's eyes and don't see a (the) beam in our own (Am.). We see the failings of others but are blind to our own (Am.). We see the faults of others but not our own (Am.). We see the splinter in others' faults, but never the spike in our own (Am.)