The boy Samuel ministered before the Lord under Eli. In those days the word of the Lord was rare; there were not many visions. One night Eli, whose eyes were becoming so weak that he could barely see, was lying down in his usual place. The lamp of God had not yet gone out, and Samuel was lying down in the house of the Lord, where the ark of God was. Then the Lord called Samuel. Samuel answered, “Here I am.” And he ran to Eli and said, “Here I am; you called me.” But Eli said, “I did not call; go back and lie down.” So he went and lay down. –1 Samuel 3:1-5

They had as king over them the angel (demon) of the Abyss, whose name in Hebrew is Abaddon and in Greek is Apollyon (that is, Destroyer).    –Revelation 9:11

Be alert and of sober mind. Your enemy the devil prowls around like a roaring lion looking for someone to devour. –1 Peter 5:8

The natural man does not receive the things of the Spirit of God, for they are foolishness to him; nor can he know them, because they are spiritually discerned.    –1 Corinthians 2:14 (NKJV)

To another discerning of spirits. –1 Corinthians 12:10 (KJV)