Paul speaks about youthful lusts as if they were a dangerous person or animal that Timothy should run away from. Alternate translation: "Completely avoid youthful lusts" or "Absolutely refuse to do the wrong things that young people strongly desire to do" (See: [[rc://en/ta/man/translate/figs-metaphor]])
Here "Pursue" means the opposite of "Flee." Paul speaks of righteousness as if it were an object that Timothy should run towards because it will do him good. Alternate translation: "Try your best to obtain righteousness" or "Seek after righteousness" (See: [[rc://en/ta/man/translate/figs-metaphor]])
Possible meanings are 1) Paul wants Timothy to join with other believers in pursuing righteousness, faith, love, and peace, or 2) Paul wants Timothy to be at peace and not argue with other believers.
Here "call on the Lord" is an idiom that means to trust and worship the Lord. Alternate translation: "those who worship the Lord" (See: [[rc://en/ta/man/translate/figs-idiom]])
Here "clean" is a metaphor for something pure or sincere. And, "heart" here is a metonym for "thoughts" or "emotions." Alternate translation: "with a sincere mind" or "with sincerity" (See: [[rc://en/ta/man/translate/figs-metaphor]] and [[rc://en/ta/man/translate/figs-metonymy]])