What is meant by "Doctrines of Devils (Demons)? Is it talking about them?
Not necessarily.
1 Timothy 4:1Now the Spirit speaketh expressly, that in the latter times some shall depart from the faith, giving heed to seducing spirits, and doctrines of devils; 2 Speaking lies in hypocrisy; having their conscience seared with a hot iron;
This prophesy is about believers giving heed to seducing spirits which in turns tempts them to follow after the rudiment in the world in seeking after them which said rudiment is the doctrines of devil. They do so in hypocrisy when knowing that the Holy Spirit is in them, but yet believe the lie that they can receive Him again after a sensational sign in the flesh. It is either He is in you or He is not. You cannot receive Him when He is already in you as promised at our salvation.
That is why the apostle John warned believers not to believe every spirit but test them; 1 John 4:1 KJV The test of that faith is by how anyone says where Jesus Christ dwells "presently" as being in our flesh in 1 John 4:2 KJV Not many Christians see that 1 John 4:2 KJV being the same examination of our faith in 2 Corinthians 13:5 KJV, but it is, because 1 John 4:3 KJV goes to any one confessing that Jesus Christ is NOT in the flesh "presently" as saying the Spirit of Christ is in the worship place, and so that is how one tests the spirits. The conformation is found in 1 John 4:4 KJV in greater is He that is in you than he that is in the world ( or outside of you. )
Believers that are Catholics, Pentecostals, & Charismatics will attest to receiving what they believe was the Holy Spirit apart from salvation by a sign of tongues without interpretation or other sensational signs in the flesh that brings about confusion like falling backwards and the like. This is where it becomes another calling and thus another gospel when they preach that experience for other believers to seek after receiving Jesus Christ again or the Holy Spirit again.
2 Corinthians 11:3 But 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. 4 For if he that cometh preacheth another Jesus, whom we have not preached, or if ye receive another spirit, which ye have not received, or another gospel, which ye have not accepted, ye might well bear with him.
Paul was addressing this falling away from the faith of 1 Timothy 4:1-2 as starting to happen already back in his day as that iniquity was already at work whereby God will permit a strong delusion to occur when saved believer believe the lie that they can receive the Holy Spirit apart from salvation in 2 Thessalonians 2nd chapter BUT Paul goes on to reprove such iniquity by reminding believers the tradition taught of us as to the ONLY TIME when the Holy Spirit is received which was at the calling of the gospel when we had first believed in Jesus Christ.
2 Thessalonians 2:13 But we are bound to give thanks alway to God for you, brethren beloved of the Lord, because God hath from the beginning chosen you to salvation through sanctification of the Spirit and belief of the truth: 14 Whereunto he called you by our gospel, to the obtaining of the glory of our Lord Jesus Christ. 15 Therefore, brethren, stand fast, and hold the traditions which ye have been taught, whether by word, or our epistle.
So that is why seducing spirits was first mentioned in that verse for how believers are following after the doctrines of devils because that is how the world receives spirits by seeing it received after a sign in the flesh.
John 14:16 And I will pray the Father, and he shall give you another Comforter, that he may
abide with you for ever; 17 Even the Spirit of truth; whom the world cannot receive, because it seeth him not, neither knoweth him: but ye know him; for he dwelleth with you, and shall be in you.
So by seducing spirits whereby believers are misled into chasing after them are actually doing the doctrines of devils in seeking to receive spirits after a sign in the flesh; even tongues without interpretation which is not God's gift of tongues.
Isaiah 8:19 And when they shall say unto you, Seek unto them that have familiar spirits, and unto wizards that peep, and that mutter: should not a people seek unto their God? for the living to the dead?
Matthew 12:39 But he answered and said unto them, An evil and adulterous generation seeketh after a sign; and there shall no sign be given to it, but the sign of the prophet Jonas:
That was the spiritual fornication that the church at Thyatira was committing, as they utter the depths of Satan for which they speak.
Revelation 2:18 And unto the angel of the church in Thyatira write; These things saith the Son of God, who hath his eyes like unto a flame of fire, and his feet are like fine brass; 19 I know thy works, and charity, and service, and faith, and thy patience, and thy works; and the last to be more than the first. 20 Notwithstanding I have a few things against thee, because thou sufferest that woman Jezebel, which calleth herself a prophetess, to teach and to seduce my servants to commit fornication, and to eat things sacrificed unto idols.
21 And I gave her space to repent of her fornication; and she repented not. 22 Behold, I will cast her into a bed, and them that commit adultery with her into great tribulation, except they repent of their deeds. 23 And I will kill her children with death; and all the churches shall know that I am he which searcheth the reins and hearts: and I will give unto every one of you according to your works. 24 But unto you I say, and unto the rest in Thyatira, as many as
have not this doctrine, and which have not known the depths of Satan, as they speak; I will put upon you none other burden.
25 But that which ye have already hold fast till I come.
So keeping the faith is the good fight and that faith in Jesus Christ is that He is in us since our salvation at the calling of the gospel when we had first believed.
Colossians 1:20 And, having made peace through the blood of his cross, by him to reconcile all things unto himself; by him, I say, whether they be things in earth, or things in heaven. 21 And you, that were sometime alienated and enemies in your mind by wicked works, yet now hath he reconciled 22 In the body of his flesh through death, to present you holy and unblameable and unreproveable in his sight: 23 If ye continue in the faith grounded and settled, and be not moved away from the hope of the gospel, which ye have heard, and which was preached to every creature which is under heaven; whereof I Paul am made a minister; ......27 To whom God would make known what is the riches of the glory of this mystery among the Gentiles
; which is Christ in you, the hope of glory: 28 Whom we preach, warning every man, and teaching every man in all wisdom; that we may present every man perfect in Christ Jesus: