en_tn/luk/15/03.md

Jesus spoke this parable to them

"To them" refers to the religious leaders.

Which one of you . . will not leave the ninety nine . . and go after . . until he finds it?

This is a rhetorical question. Jesus was reminding the people that if any of them lost one of their sheep, they would certainly go looking for it. This can be translated as a statement as in the UDB. (See: rc://en/ta/man/translate/figs-rquestion) Some languages have ways of showing that this is a hypothetical situation and not a story about a particular person who has lost a sheep. (See: rc://en/ta/man/translate/figs-hypo)

Which one of you, if he has a hundred sheep

Since the parable starts with "Which one of you", some languages would continue the parable in the second person "if you have a hundred sheep." (See: rc://en/ta/man/translate/figs-123person)