1 Corinthians 8

1 Now about food sacrificed to idols: We know that “We all possess knowledge.” But knowledge puffs up while love builds up.
Knowledge is power, power can make us prideful and pride can make us rely on our own motives rather than obeying God's call to us. Love on the other hand, is unconditional and nurturing. We prioritise others over ourselves for the sake of love. This is something I can struggle with, I have issues with indifference. People who were sheltered are particularly hard for me to love, as to me they had life a lot easier and different to me (this is a very unbiblical mentality.)
9 Be careful, however, that the exercise of your rights does not become a stumbling block to the weak.
This is the reason why I probably would never smoke in front of scy student. I can never be sure how far their imagination can stretch to. My comfortably and convenience are far less valuable than the conciseness of someone young in their faith as they could either be offended or led astray.