Gad was a seer or prophet in the Hebrew Bible. He was one of the personal prophets of King David of Israel and some of his writings are believed to be included in the Books of Samuel. He is first mentioned in 1 Samuel 22:5 telling David to return to the land of Judah.
The most important Biblical reference to Gad is 2 Samuel 24:11-13, where after David confesses his sin of taking a census of the people of Israel and Judah, God sends Gad to David to offer him his choice of three forms of punishment.
The Chronicles of Gad the seer
The words, or chronicle, of Gad the seer are mentioned in 1 Chronicles 29:29 and are generally considered a lost text.