Quran 2:169 — The Heifer (Al-Baqarah)

He only commands you to commit evil and vice, and to say about GOD what you do not know.

[2:168] O people, eat from the earth's products all that is lawful and good, and do not follow the steps of Satan; he is your most ardent enemy.

[2:170] When they are told, "Follow what GOD has revealed herein," they say, "We follow only what we found our parents doing." What if their parents did not understand, and were not guided?