'Weak Conscience' in the Bible

However, not all [believers] have this knowledge. But some, being accustomed [throughout their lives] to [thinking of] the idol until now [as real and living], still eat food as if it were sacrificed to an idol; and because their conscience is weak, it is defiled (guilty, ashamed).

For if someone sees you, the one who has this knowledge, dining in an idol’s temple, won’t his weak conscience be encouraged to eat food offered to idols?

But when ye sin so against the brethren, and wound their weak conscience, ye sin against Christ.