'Watchman' in the Bible

Son of man, I have made you a watchman to the house of Israel: therefore hear the word from my mouth, and give them warning from me.

Son of man, speak to the children of your people, and tell them, When I bring the sword on a land, and the people of the land take a man from among them, and set him for their watchman;

But if the watchman sees the sword come, and doesn't blow the trumpet, and the people aren't warned, and the sword comes, and take any person from among them; he is taken away in his iniquity, but his blood will I require at the watchman's hand.

So you, son of man, I have set you a watchman to the house of Israel; therefore hear the word at my mouth, and give them warning from me.