down to a gnat 's eyebrow
Fig. down to the smallest detail. He described what the thief was wearing down to a gnat's eyebrow. No use trying to sneak anything out of the refrigerator. Mom knows what's in there, down to a gnat's eyebrow.
strain at gnats and swallow camels
Prov. to criticize other people for minor offenses while ignoring major offenses. (Biblical.) Jill: Look at that. Edward is combing his hair at his desk. How unprofessional. Jane: Don't strain at gnats and swallow camels. There are worse problems than that around here.