1) Their confession of Jesus:

“1 Beloved, believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world. 2Hereby know ye the Spirit of God: Every spirit that confesseth that Jesus Christ is come in the flesh is of God: 3And every spirit that confesseth not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist, whereof ye have heard that it should come; and even now already is it in the world.” 1 John 4:1-3

2) Their relationship with the world:

“5They are of the world: therefore speak they of the world, and the world heareth them.” 1 John 4:5

“15 Love not the world, neither the things that are in the world. If any man love the world, the love of the Father is not in him. 16For all that is in the world, the lust of the flesh, and the lust of the eyes, and the pride of life, is not of the Father, but is of the world. 17And the world passeth away, and the lust thereof: but he that doeth the will of God abideth for ever.” 1 John 2:15-17

“4 Ye adulterers and adulteresses, know ye not that the friendship of the world is enmity with God? whosoever therefore will be a friend of the world is the enemy of God.” James 4:4

3) How they receive Christianity:

“6 We are of God: he that knoweth God heareth us; he that is not of God heareth not us. Hereby know we the spirit of truth, and the spirit of error.” 1 John 4:6

4) Their attitude toward the commandments of God:

“20 For if our heart condemn us, God is greater than our heart, and knoweth all things. 21Beloved, if our heart condemn us not, then have we confidence toward God. 22And whatsoever we ask, we receive of him, because we keep his commandments, and do those things that are pleasing in his sight. 23And this is his commandment, That we should believe on the name of his Son Jesus Christ, and love one another, as he gave us commandment. 24And he that keepeth his commandments dwelleth in him, and he in him. And hereby we know that he abideth in us, by the Spirit which he hath given us.” 1 John 3:20-24

“15 If ye love me, keep my commandments.” John 14:15

5) Love of the brethren:

“7 Beloved, let us love one another: for love is of God; and every one that loveth is born of God, and knoweth God. 8He that loveth not knoweth not God; for God is love. 9In this was manifested the love of God toward us, because that God sent his only begotten Son into the world, that we might live through him. 10Herein is love, not that we loved God, but that he loved us, and sent his Son to be the propitiation for our sins. 11Beloved, if God so loved us, we ought also to love one another. 12No man hath seen God at any time. If we love one another, God dwelleth in us, and his love is perfected in us. 13Hereby know we that we dwell in him, and he in us, because he hath given us of his Spirit. 14And we have seen and do testify that the Father sent the Son to be the Saviour of the world. 15Whosoever shall confess that Jesus is the Son of God, God dwelleth in him, and he in God. 16And we have known and believed the love that God hath to us. God is love; and he that dwelleth in love dwelleth in God, and God in him. 17Herein is our love made perfect, that we may have boldness in the day of judgment: because as he is, so are we in this world. 18There is no fear in love; but perfect love casteth out fear: because fear hath torment. He that feareth is not made perfect in love. 19We love him, because he first loved us. 20 If a man say, I love God, and hateth his brother, he is a liar: for he that loveth not his brother whom he hath seen, how can he love God whom he hath not seen? 21And this commandment have we from him, That he who loveth God love his brother also.” 1 John 4:7-21

“11 For this is the message that ye heard from the beginning, that we should love one another. 12Not as Cain, who was of that wicked one, and slew his brother. And wherefore slew he him? Because his own works were evil, and his brother's righteous. 13Marvel not, my brethren, if the world hate you. 14We know that we have passed from death unto life, because we love the brethren. He that loveth not his brother abideth in death. 15Whosoever hateth his brother is a murderer: and ye know that no murderer hath eternal life abiding in him. 16Hereby perceive we the love of God, because he laid down his life for us: and we ought to lay down our lives for the brethren.” 1 John 3:11-16

“34 A new commandment I give unto you, That ye love one another; as I have loved you, that ye also love one another. 35By this shall all men know that ye are my disciples, if ye have love one to another.” John 13:34-35

“12 This is my commandment, That ye love one another, as I have loved you. 13Greater love hath no man than this, that a man lay down his life for his friends. 14Ye are my friends, if ye do whatsoever I command you. 15Henceforth I call you not servants; for the servant knoweth not what his lord doeth: but I have called you friends; for all things that I have heard of my Father I have made known unto you.” John 15:12-15

6) The indwelling Holy Spirit:

“4 Ye are of God, little children, and have overcome them: because greater is he that is in you, than he that is in the world. 5They are of the world: therefore speak theyof the world, and the world heareth them. 6We are of God: he that knoweth God heareth us; he that is not of God heareth not us. Hereby know we the spirit of truth, and the spirit of error.” 1 John 4:4-6

7) The Word of God: 1 John 4:6 (above)

“10 He that believeth on the Son of God hath the witness in himself: he that believeth not God hath made him a liar; because he believeth not the record that God gave of his Son.” 1 John 5:10

“16 All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: 17That the man of God may be perfect, thoroughly furnished unto all good works.” 2 Timothy 3:16-17

“4 In whom the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ, who is the image of God, should shine unto them.” 2 Corinthians 4:4

Remember, EVERY spirit (we are spirits clothed in a fleshly body) who inspires any teacher to deny the incarnation of Jesus; His passion, death, bodily resurrection, and bodily ascension to heaven is not of God, and is antichrist. Re-read beginning scriptures above in 1 John 4:2-3.