(Devarim 12:5) "But to the place that the L-rd your G-d will choose of all your tribes": by word of a prophet. I might think, wait until a prophet tells you; it is, therefore, written "His dwelling shall you seek and you shall come there": Seek to find it and then the prophet will tell you. And thus do we find with David (Psalms 132:1-5) "Remember, O L-rd, unto David, all of his affliction. How he swore to the L-rd, vowed to the Might of Jacob: I shall not go up to the bed that is spread for me; I shall not give sleep to my eyes, slumber to my eyelids, before I find a place for the L-rd, a resting place for the Might of Jacob."
And whence is it derived that he wrought only by word of a prophet? From (II Samuel 24:18) "And Gad came to David on that day and said to him: Arise and set up an altar to the L-rd on the threshing floor of Aravna the Yevussi," and (II Chronicles 3:1) "And Solomon began building the Temple of the L-rd in Jerusalem on Mount Moriah, where He had appeared to his father David."