en_tn/2sa/15/19.md

Ittai

The name of a man. (See: rc://en/ta/man/translate/translate-names)

Gittite

This is the name of a people group.

Why did you go you with us, too?

This is indicating that the king had not asked them to go along. AT: "I do not want to cause you to wonder around with us." (See: rc://en/ta/man/translate/figs-rquestion)

Since you just left yesterday

This is exaggeration used for emphasis. Ittai the Gittite had been with David at least 20 years. (See: rc://en/ta/man/translate/figs-hyperbole)

May loyalty and faithfulness go with you

"May Yahweh bless you always."