He is the beginning, producing the causes which unite (the soul with the body), and, being above the three kinds of time (past, present, future), he is seen as without parts, after we have first worshipped that adorable god, who has many forms, and who is the true source (of all things), as dwelling in our own mind.

In plain words: God is the beginning and causes the soul to be joined to the body. He is beyond past, present and future, and he is whole, without parts. We see him this way after we first worship him, the source of all, as living in our own mind.