en_tn/act/20/31.md

be on guard. Remember

"be on guard and remember" or "be on guard as you remember"

be on guard

"be awake and alert" or "watch out." Christian leaders being alert about anyone that may harm the community of believers is spoken of as if they were guards in an army watching out for the enemy army. (See: rc://en/ta/man/translate/figs-metaphor)

Remember that

"Continue to remember that" or "Do not forget that"

for three years I did not stop instructing ... night and day

Paul did not teach them continuously for three years, but over the space of three years. (See: rc://en/ta/man/translate/figs-hyperbole)

I did not stop instructing

"I did not stop warning"

with tears

Here "tears" refers to Paul's crying because of the strong emotion of concern he felt while he was warning the people. (See: rc://en/ta/man/translate/figs-metonymy)