In a nine-part series John Piper recently did on Marriage, Christ, and Covenant: One Flesh for the Glory of God, his last sermon was directed towards singles.
It is entitled "Single in Christ: A Name Better Than Sons and Daughters."
It was so encouraging as well as challenging.
I've not yet listen to the first eight sermons in the series, but I wholly expect them to be excellent and right on target as well. If you are married, you might want to take a