On our way to the shopping center (6 miles) my good wife said "keep your mind on your driving". I hark back to a long lost military flic:
The hero walked into a room meaning to kill some armed enemies sitting around a table. He instantaneously evaluated each man according to readiness: the guy already moving got the first bullet, the man most obviously in charge got the next, and so on sequentially down to the last man, the sluggard.
So it is with life; we prioritize: the most important thing first; when we don't have our focus, we mess up.
In Blake's myth the most important thing is neglected by those who fall asleep in Beulah, and then into Ulro. They have forgotten the primary thing, the Spirit, Life Eternal. Drowned in the sea of time and space they can do nothing right; "the lust of the flesh, and the lust of the eyes, and the pride of life" have taken possession of them (us!).
Like Buddha they have to live through the mistakes of life, try them all and learn the hard way.
Finally reborn, generated and regenerated, they gain their focus: they learn to refuse all the distraction and find their way back to the Garden.
Purity of Heart is to Will One Thing (Kierkegaard)