Here "searches you out" is a metaphor meaning "examines you." Job uses this question to warn his friends that if God were to examine them, he would say that what they are doing is wrong. AT: "When God examines you, it will not be good for you." (See: [[rc://en/ta/man/translate/figs-rquestion]])
Job uses this question to warn his friends that God knows the truth about them. AT: "You might be able to deceive men, but you cannot deceive God." (See: [[rc://en/ta/man/translate/figs-rquestion]])
"if you secretly show favor to another." Showing partiality refers to saying only good things about someone so that the judge will say that the person is good. Doing this in secret means pretending to speak fairly, but really favoring one person over another.