Albert Barnes Commentary 1 Corinthians 7:9

"But if they have not continency, let them marry: for it is better to marry than to burn." — 1 Corinthians 7:9 (ASV)

But if they cannot contain. If they have not the gift of continence; if they cannot be secure against temptation; if they have not strength of virtue enough to preserve them from the danger of sin, and of bringing reproach and scandal on the church.

It is better. It is to be preferred.

Than to burn. The passion here referred to is often compared to a fire. See Virgil's Aeneid 4.68. It is better to marry, even with all the inconveniences attending the marriage life in a time of distress and persecution in the church (1 Corinthians 7:26), than to be the prey of raging, consuming, and exciting passions.

The word "contain" signifies "to not have continence." See also let them marry (1 Timothy 5:14).