2Jn vv. 7-13 Deceivers have gone out into the world

(2Jn vv. 7-13) Deceivers have gone out into the world
[7] Many deceivers have gone out into the world, those who do not acknowledge Jesus Christ as coming in the flesh; such is the deceitful one and the antichrist. [8] Look to yourselves that you do not lose what we worked for but may receive a full recompense. [9] Anyone who is so "progressive" as not to remain in the teaching of the Christ does not have God; whoever remains in the teaching has the Father and the Son. [10] If anyone comes to you and does not bring this doctrine, do not receive him in your house or even greet him; [11] for whoever greets him shares in his evil works. [12] Although I have much to write to you, I do not intend to use paper and ink. Instead, I hope to visit you and to speak face to face so that our joy may be complete. [13] The children of your chosen sister send you greetings.

(CCC 465) The first heresies denied not so much Christ's divinity as his true humanity (Gnostic Docetism). From apostolic times the Christian faith has insisted on the true incarnation of God's Son "come in the flesh". (Cf. 1 Jn 4:2-3; 2 Jn 7). But already in the third century, the Church in a council at Antioch had to affirm against Paul of Samosata that Jesus Christ is Son of God by nature and not by adoption. The first ecumenical council of Nicaea in 325 confessed in its Creed that the Son of God is "begotten, not made, of the same substance (homoousios) as the Father", and condemned Arius, who had affirmed that the Son of God "came to be from things that were not" and that he was "from another substance" than that of the Father. (Council of Nicaea I (325): DS 130, 126). (CCC 675) Before Christ's second coming the Church must pass through a final trial that will shake the faith of many believers (Cf. Lk 18:8; Mt 24:12). The persecution that accompanies her pilgrimage on earth (Cf. Lk 21:12; Jn 15:19-20) will unveil the "mystery of iniquity" in the form of a religious deception offering men an apparent solution to their problems at the price of apostasy from the truth. The supreme religious deception is that of the Antichrist, a pseudo-messianism by which man glorifies himself in place of God and of his Messiah come in the flesh (Cf. 2 Th 2:4-12; 1 Th 5:2-3; 2 Jn 7; 1 Jn 2:18, 22).