This Bible contradiction is from the Skeptic's Annotated Bible.
2 Timothy 3:16 View context
All scripture [is] given by inspiration of God, and [is] profitable for doctrine, for reproof, for correction, for instruction in righteousness:
1 Corinthians 7:12 View context
But to the rest speak I, not the Lord: If any brother hath a wife that believeth not, and she be pleased to dwell with him, let him not put her away.
1 Corinthians 7:25 View context
Now concerning virgins I have no commandment of the Lord: yet I give my judgment, as one that hath obtained mercy of the Lord to be faithful.