Though Satan has been defeated by Jesus Christ, he continues as an unrelenting foe in his warfare against God and mankind.
The Lord said to the Pharisees who hated Him:
"Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own; for he is a liar, and the father of it. And because I tell you the truth, ye believe me not" (Jn. 8:44-45).
Satan may use the truth, but only to eventually propagate a lie. It is always a subterfuge for promoting his deceptions. Using his network of deception through demonic forces and duped people, he promotes false doctrines in the name of God (2 Cor. 11:3; Eph. 4:14; 1 Tim. 4:1-4; 2 Tim. 3:13; 2 Thess. 2:10).
Satan has the power of influence and blinding. He blinds the minds of the unbelieving (2 Corinthians 4:4). He prevents the gospel from entering their hearts (Matthew 13:19; Luke 8:11). Satan speaks through fortunetellers (Acts 16:16), cult leaders (1 Timothy 4:1-2), and false preachers (2 Corinthians 11: 13-15). He seeks to deceive about his existence, his purposes, his activities, and his coming defeat. He is the deceiver of the whole world (Revelation 12:8). His ultimate deception will be in the anti-christ (2 Thessalonians 2:9).