Bible Verses About Prophets: One generally attached to the king's household

For when David was up in the morning, the word of the LORD came unto the prophet Gad, David's seer, saying,

And he set the Levites in the house of the LORD with cymbals, with psalteries, and with harps, according to the commandment of David, and of Gad the king's seer, and Nathan the prophet: for so was the commandment of the LORD by his prophets.

And the singers the sons of Asaph were in their place, according to the commandment of David, and Asaph, and Heman, and Jeduthun the king's seer; and the porters waited at every gate; they might not depart from their service; for their brethren the Levites prepared for them.