Okay this one I remember well> copied from LeClaire's website article.
David was talking with the prophet Nathan—the same prophet who later would rebuke him for committing adultery with Bathsheba and setting up the murder of her husband, Uriah the Hittite (2 Sam. 12). David was dismayed because God was dwelling inside tent curtains while he lived in a house of cedar (2 Sam. 7:2).
That's when Nathan spoke these words from his anointed mouth: "Go, do all that is in your heart, for the Lord is with you" (2 Sam. 7:3). Although this wasn't a "thus saith the Lord" type of prophetic word, it was a word of approval from a trusted prophetic voice in David's life. David was looking for prophetic counsel about his plans to build a house for the Lord, seeking confirmation that it was in God's will. David seemed to receive that confirmation, but the Lord took steps to correct Nathan's pure-hearted mistake before the king got too far.
God sent Nathan back to David with a bona fide prophetic word that contradicted his friendly counsel to "do all that is in your heart, for the Lord is with you." The Lord did not want David to build him a house but rather committed to establishing David's throne forever (2 Sam. 7:4-17).