Justin Martyr wrote:
For the apostles, in the memoirs composed by them, which are called Gospels, have thus delivered unto us what was enjoined upon them; that Jesus took bread, and when He had given thanks, said, "This do ye in remembrance of Me..." First Apology 66This quote is interesting because: A) it identifies "the Gospels" (plural) as the memoirs of the Apostles, and B) because Justin ties the Gospels with the Eucharistic liturgy.
As we study the origins of the Gospels, we must be mindful of the fact that they were written to be read at Eucharistic assemblies. They were not written for private Bible studies, small groups, or academic seminars on Jesus.
The context of their composition does not exclude the Gospels being used at Bible studies or wherever, but we cannot think of the Gospels as somehow broken off or removed from the Eucharist and the liturgy of the Church. This should be inconceivable for the Christian.