Complex sentence: God of Israel is a descriptive term and often a title for the central deity that is the subject of worship in the Hebrew Bible, the deity of the ancient Israelites, and the only deity worshiped today in Judaism.
Split into simpler sentences: God of Israel is a descriptive term for the central deity that is the main subject of worship as described in the Hebrew Bible. The God of Israel was the deity of the ancient Israelites and is today the only deity worshiped in Judaism.