The Paul seen in Galatians is on a clear mission to separate Christianity from Jewish Law. However, before he can accomplish this goal, he first validates his own authority by stating his source: “I did not receive it from a human source, nor was I taught it, but I received it through a revelation of Jesus Christ” [Gal 1:12]. He claims” [God] set me apart before I was born and called me through his grace” [Gal 1:15], further legitimizing his word and connection with God.
After proving his worthiness, he then approaches the role of Jewish Law. He clarifies his interpretation using Jesus Christ: “We ourselves are Jews by birth and not Gentile sinners; yet we know that a person is justified not by the works of the law but through faith in Jesus Christ” [Gal. 2:15-16]. The life of Jesus Christ is justification for the separation as he further states: “I do not nullify the grace of God; for if justification comes through the law, then Christ died for nothing” [Gal. 2:21]. In other words, the good graces of God no longer require strict adherence to the Law. By believing in God and the message of Jesus Christ, salvation is achieved. He goes on to that that, “For freedom Christ has set us free. Stand firm, therefore, and do not submit again to a yoke of slavery” [Gal. 5:1]. While I am uncertain of the exact reference, I do find it reasonable to assume that ‘slavery’ in this instance is pointing towards Jewish Law.
The understanding of Marcion evolves over time with Justin Martyr giving a limited description. He focuses solely on the belief Marcionites held of the existence of two Gods [one of the Old Testament and one of the “New Testament”]. He also mentions other stories of them committing shameful deeds [i.e. promiscuous intercourse and eating human flesh], but notes their questionable nature. Regardless, he includes: “But I have a treatise against all heresies which have arisen already composed, which I will give you if you wish to read it” [I Apology 26:189-190].
Irenaeus broadens the understanding of Marcion, mentioning the removal of Jewish Law and his works involving the Gospel: “. . . he mutilated the Gospel according to Luke, discarding all that is written about the birth of the Lord” [Against Heresies 1.27:6]. In addition, he spends extra effort connecting Marcion with Simon Magus stating that “all those who in any way adulterate the truth and do injury to the preaching of the Church are the disciples and successors of Simon, the magician of Samaria” [Against Heresies 1.27:12].
Tertullian certainly holds no punches in regards to his feelings: “the most barbarous and melancholy thing about Pontus is that Marcion was born there, more uncouth than a Scythian, more unsettled than a Wagon-dweller, more uncivilized than a Massagete . . .” [Against Marcion 1.1]. The comparisons continue, but the premise is clear: Tertullian is not a fan. He reinforces the notion of Marcion’s two God theory, the bastardization of the Gospel of Luke, and the removal of Jewish Law while also adding new ideas. This includes the notion that Christ was not of flesh.
In line with the previous writings, Epiphanius regards Marcion as a heretic, but the description of Marcion as an individual is expanded upon. More claims of his practices are added, noting that “Marcion also preaches virginity, and fasting on Saturday” [Panarion 42.3.3].