Charles Ellicott Commentary John 5:18

"For this cause therefore the Jews sought the more to kill him, because he not only brake the sabbath, but also called God his own Father, making himself equal with God." — John 5:18 (ASV)

For “had broken,” read did He break, and for “His Father,” His own Father. They recognize as beyond doubt what He means by the term My Father, and the attribute of ceaseless energy. It was a claim which no one else had ever made, that God was in a peculiar sense His own Father. They feel it is a claim to divinity, making Himself equal with God.

The more to kill him.—This implies what is included in the persecution of John 5:16. (Mark 3:6; Luke 6:7–11.)