A fair number of people will tell you that 'they belong to a religion of one' or that 'they have their own religion' or that 'they don't go to church, but they pray'.
According to Blake these people walk on the right track; that's certainly what he did: "I must create a system or be enslaved by another man's."
You and I have the same choice: to live by "another man's" values or to see things for ourselves (Blake called these choices 'single vision' or 'double vision.)
Satan (the Selfhood or tyrannical Society) constantly works to fit us for the 'mind forg'd manacles': School exists primarily to 'socialize' a child (to conform to the ways 'Society' has chosen for us). Most of us obey, but a fair number of kids don't buy Society's program; Blake fortunately escaped that bane.
Blake considered the greatest sin to be 'hindering another' (Erdman 601). His primary aim was to "raise men to a perception of the Infinite" (MHH plate 13).
The system Blake created bears a close resemblance to the Perennial Philosophy; when he had completed it, Jesus, the Imagination (or Jesus the Forgiveness) was Central.