Midrash for Zevachim 237:1

דכתיב (מלכים א ב, יא) והימים אשר מלך דוד על ישראל מ' שנה בחברון מלך ז' שנים [וגו']

for it is written, And the days that David reigned over Israel were forty years: seven years reigned he in Hebron, [and thirty and three years reigned he in Jerusalem].<span class="x" onmousemove="('comment',' I Kings II, 11.');">¹</span> Now of Solomon it is written, And he began to build.

Sifrei Devarim