RobH_en_tn/mat/05/10.md

those who have been persecuted

This can be stated in active form. Alternate translation: "those people whom others treat unfairly" (See: rc://en/ta/man/translate/figs-activepassive)

for righteousness' sake

"because they do what God wants them to do"

theirs is the kingdom of heaven

Here "kingdom of heaven" refers to God's rule as king. This phrase is only in the book of Matthew. If possible, keep "heaven" in your translation. See how you translated this in Matthew 5:3. Alternate translation: "for God in heaven will be their king" (See: rc://en/ta/man/translate/figs-metonymy)