Son of man, I have made you a watchman for the house of Israel. Whenever you hear a word from my mouth, you shall give them warning from Me. If I say to the wicked, ‘You shall surely die,’ and you give him no warning, nor speak to warn the wicked from his wicked way, to save his life, that wicked person shall die for his iniquity, but his blood I will require at your hand. But if you warn the wicked, and he does not turn from his wickedness, or from his wicked way, he shall die for his iniquity, but you will have delivered your soul.

Ezekiel 3:17-19 (ESV)