Tafsir of Al-Anbiya' 21:86

"And We admitted them into Our mercy..."

The discussion regarding this is in the same style as its predecessor mentioned just moments ago.

"...indeed, they were of the righteous."

Meaning: those perfect in righteousness due to their immunity (infallibility) from sins. The sentence occupies the position of a rationale (ta'lil). There is no "explaining a thing by itself" here, and there is no need to consider the 'min' (of) as beginning (ibtida'iyyah), as becomes apparent upon the slightest consideration.