Both marriage and singleness are gifts from God. It's in the Bible, I Corinthians 7:6-7, TLB. "I'm not saying you must marry, but you certainly may if you wish. I wish everyone could get along without marrying, just as I do. But we are not all the same. God gives some the gift of a husband or wife, and others He gives the gift of being able to stay happily unmarried."
A good reason to remain single is to use the time and freedom to serve God. It's in the Bible, I Corinthians 7:29-31, TLB. "The important thing to remember is that our remaining time is very short [and so are our opportunities for doing the Lord's work]. For that reason those who have wives should stay as free as possible for the Lord; happiness or sadness or wealth should not keep anyone from doing God's work. Those in frequent contact with the exciting things the world offers should make good use of their opportunities without stopping to enjoy them; for the world in its present form will soon be gone."