https://en.wikipedia.org/wiki/Gospel_of_Marcion
Indeed, St Paul's letters are the earliest recorded New Testament books. Marcion's cannon grouped most of the letters of Paul into a collection termed the Apostolikon, which was the centerpiece of his branch of early Christianity:
https://en.wikipedia.org/wiki/Marcionism
"The premise of Marcionism is that many of the teachings of Christ are incompatible with the actions of the God of the Old Testament. Focusing on the Pauline traditions of the Gospel, Marcion felt that all other conceptions of the Gospel, and especially any association with the Old Testament religion, was opposed to, and a backsliding from, the truth. He further regarded the arguments of Paul regarding law and gospel, wrath and grace, works and faith, flesh and spirit, sin and righteousness, death and life, as the essence of religious truth. He ascribed these aspects and characteristics as two principles, the righteous and wrathful God of the Old Testament, who is at the same time identical with the creator of the world, and a second God of the Gospel who is only love and mercy.[11]
Marcionites held that the God of the Hebrew Bible was inconsistent, jealous, wrathful and genocidal, and that the material world he created was defective, a place of suffering; the God who made such a world is a bungling or malicious demiurge."
[...]
"In Marcionite belief, Christ was not a Jewish Messiah, but a spiritual entity that was sent by the Monad to reveal the truth about existence, thus allowing humanity to escape the earthly trap of the demiurge. Marcion called God, the Stranger God, or the Alien God, in some translations, as this deity had not had any previous interactions with the world, and was wholly unknown. See also the Unknown God of Hellenism and the Areopagus sermon."