Matthew 19:12
"For there are some eunuchs, which were so born from their mother’s womb: and there are some eunuchs, which were made eunuchs of men: and there be eunuchs, which have made themselves eunuchs for the kingdom of heaven’s sake. He that is able to receive it, let him receive it."
Cross References (ranked by relevance)
1 Corinthians 9:5
Have we not power to lead about a sister, a wife, as well as other apostles, and as the brethren of the Lord, and Cephas?
Isaiah 39:7
And of thy sons that shall issue from thee, which thou shalt beget, shall they take away; and they shall be eunuchs in the palace of the king of Babylon.
1 Corinthians 9:15
But I have used none of these things: neither have I written these things, that it should be so done unto me: for it were better for me to die, than that any man should make my glorying void.