When we believed upon Christ we were delivered from the power of darkness and translated into the kingdom of God's dear Son / Col 1:13. We were no longer of the world even though we remained in the world / Jn 15:19, 17:15,16. We were placed in Christ as a member of His body with Christ as our head / 1Cor 11:3. We are sealed and seated together in heavenly places / Eph 2:6. I wonder how many of us really meditate on that truth about our position in Christ! We are hid with Christ in God / Col 3:3 and derive our life from above and not from the world / Jm 3:17.
The unbeliever is of the world and lives in the flesh deriving his life from below through the lust of the flesh, the lust of the eyes and the pride of life / 1Jn 2:16. He may be moral and have moral light / Jn 1:9, but he is still lost and does not have the light of God and lives under the power of darkness in a world filled with iniquity. Who is the prince and power of the air / Eph 2:2? Who is the god of this world system / 2Cor 4:4? Who is the one that offered Christ all the kingdoms of the world if He would worship him / Mt 4:8,9? Who is the one that is responsible for this mystery of iniquity that is already at work / 2Thes 2:6,7?
Put it all together. If a man is not in Christ he is in the world, living in his flesh with an old sin nature, deriving his life from below that is earthy, sensual and devish / Jm 3:15. He is in a world system under a power of darkness, that is controlled by the prince and power of the air and the god of this world who has blinded his mind so that he might receive the truth. He is in constant subjection to the lust of the flesh, eyes and the pride of life with a heart that is deceitful and desperately wicked / Jer 17:9, Is 1:5. The one that we are talking about is not some wicked ruler that was concieved in siin with flesh and bones but the one who was cast out of heaven because of the iniquity that was found in him. If he was responsible for creating all the kingdoms of the earth, it would be very reasonable to assume that he is also responsible for all the religions that are of this world and not in Christ.
Do the muslims worship the god of this world just as any man that is outside of Christ? I think so! Does the moral man that does good and lives in his own moral righteousness live under the prince and power of the air, who can transform himself as a minister of righteousness and decieve the very best that humanity can offer in the flesh? I think so! Is there any that are good and doeth good?
Rom 3:9-18 What then? are we better than they? No, in no wise: for we have before proved both Jews and Gentiles, that they are all under sin;
10 As it is written, There is none righteous, no, not one:
11 There is none that understandeth, there is none that seeketh after God.
12 They are all gone out of the way, they are together become unprofitable; there is none that doeth good, no, not one.
13 Their throat is an open sepulchre; with their tongues they have used deceit; the poison of asps is under their lips:
14 Whose mouth is full of cursing and bitterness:
15 Their feet are swift to shed blood:
16 Destruction and misery are in their ways:
17 And the way of peace have they not known:
18 There is no fear of God before their eyes.
I hope that answers your question!
