John Wesley on 1 Chronicles 12:17

The God of our fathers - He calls God, the God of our fathers, both his fathers and theirs; thus he minds them, not to deal ill with him; for they were both descendents from the same patriarchs, and servants of the same God. And thus he encourages himself to believe, that God would right him, if he was abused. For he was the God of his fathers; therefore a blessing was entailed upon him: and a God to all Israel in particular, as well as a Judge to all the earth.