Charles Spurgeon Commentary 1 Corinthians 10:29

"conscience, I say, not thine own, but the other`s; for why is my liberty judged by another conscience?" — 1 Corinthians 10:29 (ASV)

That person may not be able to do it without harming himself, but I can, and I have the freedom to do so; yet, as a Christian, I am to consider his weakness, and I am not to use my freedom, so that I do not harm my brother.