Nor is that Self to be gained by one who is destitute of strength, or without earnestness, or without right meditation. But if a wise man strives after it by those means (by strength, earnestness, and right meditation), then his Self enters the home of Brahman.

In plain words: Someone who is weak, careless, or does not meditate properly cannot reach the Self. But a wise person who works at it with strength, real effort, and right meditation enters the home of Brahman.