In The Old Testament

"There shall not be found among you any one who burns his son or his daughter as an offering, any one who practices divination, a soothsayer, or an augur, or a sorcerer, or a charmer, or a medium, or a wizard, or a necromancer. For whoever does these things is an abomination to The Lord; and because of these abominable practices The Lord your God is driving them out before you. You shall be blameless before The Lord your God" (Deuteronomy 18:10-13 RSV)

"For rebellion is as the sin of divination [i.e. witchcraft], and stubbornness is as iniquity and idolatry." (1 Samuel 15:23 RSV)

In The New Testament

"Now the works of the flesh are plain: fornication, impurity, licentiousness, idolatry, sorcery, enmity, strife, jealousy, anger, selfishness, dissension, party spirit, envy, drunkenness, carousing, and the like. I warn you, as I warned you before, that those who do such things shall not inherit the Kingdom of God." (Galatians 5:19-21 RSV)

"But as for the cowardly, the faithless, the polluted, as for murderers, fornicators, sorcerers, idolaters, and all liars, their lot shall be in the lake that burns with fire and sulphur, which is the second death." (Revelation 21:8 RSV)

Salvation At Risk

God condemns witchcraft and sorcery because it involves blatant idolatry and paganism. Sometimes it even includes outright worship of Satan, making it extremely vile and wicked in God's sight, as His own Words make plain. Those who seek to obey The Lord, those whose salvation is important to them, should have absolutely nothing to do with it.

Fact Finder: What was the name of the witch who was married to King Ahab of Israel?
2 Kings 9:22
See also Jezebel