'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).

And when you sin against the brothers and sisters in this way and wound their weak conscience [by confusing them], you sin against Christ.