'Prophet' in the Bible

All Israel from Dan to Beer Sheba realized that Samuel was confirmed as a prophet of the Lord.

(Now it used to be in Israel that whenever someone went to inquire of God he would say, "Come on, let's go to the seer." For today's prophet used to be called a seer.)

Then Gad the prophet said to David, "Don't stay in the stronghold. Go to the land of Judah." So David left and went to the forest of Hereth.