12. For there are some eunuchs which were so born from their mother's womb—persons constitutionally either incapable of or indisposed to marriage.
and there are some eunuchs which were made eunuchs of men—persons rendered incapable by others.
and there be eunuchs which have made themselves eunuchs for the kingdom of heaven's sake—persons who, to do God's work better, deliberately choose this state. Such was Paul (1Co 7:7).
He that is able to receive it, let him receive it—"He who feels this to be his proper vocation, let him embrace it"; which, of course, is as much as to say—"he only." Thus, all are left free in this matter.