English Standard Version
Being therefore a prophet, and knowing that God had sworn with an oath to him that he would set one of his descendants on his throne,New International Version
But he was a prophet and knew that God had promised him on oath that he would place one of his descendants on his throne.Catholic Public Domain Version
Therefore, he was a prophet, for he knew that God had sworn an oath to him about the fruit of his loins, about the One who would sit upon his throne