1 Corinthians 8:10

For if any man see thee which hast knowledge sit at meat in the idol's temple, shall not the conscience of him which is weak be emboldened to eat those things which are offered to idols (KJV)

Then: Wright uses the word "lure." The act of the strong-conscience guy can "lure" the weak-conscience guy back into sin - sin for the weak one because they've never been able to separate the bits and pieces of what is right with the action from what is wrong with it. Verse nine started it. Verse ten finishes it. Christians are responsible for the on-going spiritual growth of fellow believers. Like it or not, everyone is a teacher, example, leader to others in the faith. The Corinthians were blessed to have Paul tell them the exact instance of this problem and be both forewarned and forearmed. They still had plenty of life time left to correct mistakes before entering eternity.

Now: We need the internal, active Spirit of the Lord to tell us when something is askew, that our actions are misdirecting fellow believers. When a other followers speak, we need to listen, not just immediately brush off any and all comments by walking down another path. Being a stumbling block is a serious offense.