When the seer sees the brilliant maker and lord (of the world) as the Person who has his source in Brahman, then he is wise, and shaking off good and evil, he reaches the highest oneness, free from passions;

In plain words: When a person sees the shining Creator and Lord, whose source is Brahman, that person becomes wise. They rise above good and bad deeds, become free of cravings, and reach the highest oneness.