'Reward' in the Bible

Now may Yahweh show loving kindness and truth to you. I also will reward you for this kindness, because you have done this thing.

I am this day weak, though anointed king; and these men the sons of Zeruiah are too hard for me. May Yahweh reward the evildoer according to his wickedness."

when someone told me, 'Behold, Saul is dead,' thinking to have brought good news, I took hold of him, and killed him in Ziklag, which was the reward I gave him for his news.

Then Ahimaaz the son of Zadok said yet again to Joab, "But come what may, please let me also run after the Cushite." Joab said, "Why do you want to run, my son, since that you will have no reward for the news?"

Your servant would but just go over the Jordan with the king. Why should the king repay me with such a reward?