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
In Isaiah 56:3, eunuchs are told not to feel excluded; this OT promise of inclusion underlies Jesus' statement that some become eunuchs for the kingdom.
In Isaiah 56:4, God blesses eunuchs who keep His covenant, reinforcing the honor of voluntary celibacy for devotion to God.
In 1 Corinthians 7:32-38, Paul explains the advantage of being unmarried for undivided devotion — echoing the 'eunuch for the kingdom' concept.
In 1 Corinthians 7:7, Paul calls celibacy a gift from God — directly relating to those who make themselves eunuchs for the kingdom.
In 1 Corinthians 7:35, Paul promotes undivided devotion to the Lord through singleness — the same goal as becoming a eunuch for the kingdom.
Isaiah 39:7 prophesies that Hezekiah's descendants will become eunuchs, providing background for Jesus' mention of those made eunuchs by men.