There are three categories of humans; 1) unregenerate mankind, 2) regenerated [saved], but carnal [fleshly, superficial] Christians, and 3) genuinely spiritual believers.

⁵ For they that are after the flesh do mind [attend to] the things of the flesh; but they that are after the Spirit [are mindful of] the things of the Spirit. ⁶ For to be carnally [fleshly] minded is death; but to be spiritually minded is life and peace. Romans 8:5-6 (KJV)

¹⁵ But he that is spiritual judgeth [discerns] all things, yet he himself is judged of no man. 1 Corinthians 2:15 (KJV)

All three categories of humans can be and most often are deceived to one degree or another. Thus, the arch-deceiver is not only the deceiver of the whole unregenerate world, but also of the children of God. The unregenerates are largely deceived with worldly temptations and humanistic ideas designed to enslave mankind under Sin and Death, and groom them for their acceptance of Antichrist’s coming tribulation rule.

There is a difference in how the Devil seeks to deceive believers. Satan foists his lying deception upon the believers at all levels, but he works his most acute strategy through subtle False Religious Teachings concerning “the things of God.” He does this through his ‘false apostles’ and ‘false teachers.’  Thus, Paul writes this to believers;

³ … I fear, lest by any means, as the serpent beguiled Eve through his subtilty, so Your Minds Should Be Corrupted from the simplicity that is in Christ. 2 Corinthians 11:3 (KJV)
¹³ For such are False Apostles, Deceitful Workers transforming themselves into the apostles of Christ, ¹⁴ And no marvel; for Satan himself is transformed into an angel of light. ¹⁵ Therefore it is no great thing if his [Satan’s] ministers also be transformed as the ministers of righteousness; whose end shall be according to their [deceitful] works. 2 Corinthians 11:13-15 (KJV)

The chief weapon which the “prince of darkness” relies upon to keep the world under his power is deception. His deception is planned to beguile men at every stage; 1) the unregenerate man is already deceived by Sin that promotes self-interest, and humanistic ideas; 2) the carnal [fleshly] Christian is superficial and thus suited to believe the lies of false teaching that appeals to their fleshly self-interest; such as ‘get your blessing’ or ‘get your healing,’ 3) but the ‘spiritual’ believers are subject to deceptions also, ones precisely fitted to the ‘spiritual believer’ who has passed out of the earlier stages into the realm where he can be seduced into the more subtle “wiles [trickeries] of the Devil.” These wiles may include ‘Bible truth out of balance’ or misapplied Bible truth, or Bible truth that is Scriptural but NOT Dispensational – such that it is NOT Applicable to members of “the body of Christ” during today’s age of “the grace of God.” Context matters in Bible study. For this I suggest my study titled ‘How to Approach the Bible’: http://www.artlicursi.com/series/how-approach-bible

Let the deception that holds the man in his unregenerate condition be removed by the gospel and he will be saved into the stage of the carnal Christian life. Let that carnal condition be removed through understanding of the Lord’s gospel of His grace, the written word of God for today, and Paul’s “revelation of the mystery” for today and he emerges into the ‘spiritual’ stage fitted for “the heavenly places.” Thus, Paul in his epistle to the Ephesians describes the ‘spiritual’ believer who finds himself contending with the very keenest workings of the ‘wiles of the deceiver’ (Eph 6:10-18). There, the deceiving spirits are actively at work attacking the minds of those who are united to the risen Lord in TRUTH.

The work of the deceivers among these saints of God is especially depicted in Paul’s Ephesians 6. There we have the veil drawn back to reveal the Satanic powers concerning their war upon the members of the church of God. Paul explains the individual believer’s armor and weapons for overcoming the enemy of their souls and God’s eternal plan of the ages.

¹⁰ Finally, my brethren, be strong in the Lord, and in the power of his might. ¹¹ Put on the whole armour of God, that ye may be able to stand against the wiles of the devil.

¹² For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high [the heavenly] places.

¹³ Wherefore take unto you the whole armour of God, that ye may be able to withstand in the evil day, and having done all, to stand. ¹⁴ Stand therefore, having your loins girt about with truth, and having on the breastplate of righteousness; ¹⁵ And your feet shod with the preparation of the gospel of peace; ¹⁶ Above all, taking the shield of faith, wherewith ye shall be able to quench all the fiery darts of the wicked. ¹⁷ And take the helmet of salvation, and the Sword of The Spirit, Which Is The Word of God: ¹⁸ Praying always with all prayer and supplication in the Spirit, and watching thereunto with all perseverance and supplication for all saints; Ephesians 6:10-18 (KJV)

From the above passage we learn that in the plan of the believer’s highest experience of union with the Lord  “in the heavenly places” is under attack of the Devil. Here we find the keenest and closest battle to be fought with the deceiver and his swarm of ‘lying spirits,’ as they attempt to Pervert The Minds Of The Believers concerning the Key Doctrinal Truths Upon Which We “Stand.” The Devil knows by now that we are destined to replace him and his host of evil spirits, then to occupy the seats of rank and authority in the government of “the heavenly places.”

Below Jesus gives us a glimpse into this onslaught of “deceiving spirits” and “lying wonders” (Rev 16:4) to come upon the world and to tempt Israel’s Messianic believers at the close of the age in the Tribulation period. In the gospel Matthew the Lord uses the word deceive in describing the special mark of the latter days saying;

⁴ And Jesus answered and said unto them, Take heed that no man DECEIVE YOU. ⁵ For many shall come in my name, saying, I am Christ; and shall deceive many. Matthew 24:4-5 (KJV)

²⁴ For there shall arise false Christs, and false prophets, and shall shew Great Signs and Wonders; insomuch that, if it were possible, they shall deceive the very elect [of Israel]. Matthew 24:24 (KJV)

(Portions of this Study are adapted from “War on the Saints,” by Jessie Penn Lewis and “Earth’s Earliest Ages” by G. H. Pember.)