1 Corinthians 7:26
I suppose therefore that this is good for the present distress, [I say], that [it is] good for a man so to be.
Note 2 at 1Co 7:26: Paul gave a very clear reason why he thought celibacy was good. It was because of the present distress. Some think that this is limited to the situation of Paul's day when there was much hostility toward Christianity. However, it is just as likely that Paul was referring to the entire condition of mankind since the Fall until the Second Coming of Christ.
Due to the fact that marriage takes a lot of effort and time, some people could profit by remaining single. This is easy to see in the case of some missionary endeavors where the minister might be gone long periods of time and face extreme hardships. In Paul's case, a wife and children would have drastically changed the way he ministered. It's one thing to put your own life at risk for the sake of the Gospel, but it is an entirely different thing when your mate or child is going to be killed for your stand of faith. By the grace of God, an individual can remain faithful in a situation like that, but Paul said it was good to avoid this temptation if God gives you the grace to remain single.
He also said in 1Co 7:32-35 that marriage causes people to be occupied with the things of this world more than single people have to be. Therefore, he advocated celibacy so that people can serve the Lord without distraction (1Co 7:35).
It needs to be noted that God's original and perfect plan for every person was marriage (Ge 2:18), but because of the corruption that is in the world (the present distress), some individuals are graced by God with the ability to remain single and will be more effective in that state.