I wrote about this little "gospel" almost two years ago in this post, but this semester I wrote a paper about it. The paper was for my "Biblical Canon" class, so I wrote a paper exploring the theology presented in the Gospel of Mary and its relationship to the biblical literature. I would still recommend reading the translation and commentary by Jean Yves-Leloup, although I read a bunch of other commentaries and articles for this paper. I liked this translation best because it was most poetic, and the commentary engaged the text in a spiritual manner rather than simply academic. So unless you want to learn really academic stuff about the text, read Leloup's version.
Most scholars assumed the Gospel of Mary was a Gnostic work because it was found bound in the same codex with two other Gnostic texts, but there was also a non-Gnostic text in the same volume so that is not a very good argument. Fragments of it were also found at Oxyrhynchus, an ancient town in Egypt with a great garbage dump that archaeologists look through. At Oxyrhynchus, no (other) Gnostic texts have been found, although thirty of the canonical books and a few others from the Apocrypha or non-canonical Christian texts have been found. Plus, unless you know information about Gnosticism from other clearly Gnostic texts, you cannot tell anything about Gnosticism from the Gospel of Mary. It doesn't even mention "gnosis," translated "knowledge" or "wisdom." In fact, wisdom is only used twice, to refer to "intoxicated wisdom" and "guileful wisdom," parts of wrath that the soul must evade. One would think a "Gnostic" text would include a positive understanding of "gnosis." The idea of gnosis is usually a secret teaching that people have to get to a certain rank in the community in order to learn, but in the Gospel of Mary, although she receives a revelation that the others don't receive, her revelation is freely given to whoever will listen--it is not a secret. So I think this text was written to be Christian, and although there are hints of what later perhaps formed into Gnosticism, there are also such hints in canonical texts such as John and Mark. Gnosticism also usually had an elaborate mythology including several gods and goddesses and a rejection of the flesh, but the Gospel of Mary does not have these (at least in the 9/19 pages we currently have).
I agree with Esther de Boer who says she thinks the Gospel of Mary was written to be a Christian text that spoke in the language of Stoicism to reach out to the Hellenistic culture. She makes many connections between the language of matter, nature, the "nous" (mind) and other things that were similar to Stoicism. The Gospel of Mary goes beyond the Stoic understanding however, because they rejected the physical world of matter and nature, and they thought perfection was attainable. The Gospel of Mary rejects the evil part of the physical world and says that evil is an improper mixture of matter and nature, but "matter" is the word it uses for what Christians might term the "fallen" parts of creation, while "nature" is the good parts of the physical world. As humans alone we cannot reach perfection, according to the Gospel of Mary, but we need the Savior, who alone can separate the improper mixture and help us focus only on the good parts of nature. (The Gospel of Mary never says the Savior is Jesus in the portion we have, but it is assumed since he is a resurrected teacher talking to a group of disciples with the names we know from the biblical texts.)
Neither does the Gospel of Mary elevate the spiritual too much. Mary asks the Savior what is responsible for understanding that a vision comes from God: is it the senses (the soul) or the spirit? He says it is neither: it is the "nous" (roughly translated "mind") which lies between the two. The nous is the soul's access to the spiritual plane, but it does not mean that the physical world of the soul is rejected. God can use the physical world to do good and to speak to people through. It is the mind which understands that something is from God, whether it is a physical event or a more spiritual event. This is interesting, because the Gospel of Mary suggests a sort of continuing revelation, but rather than this being ecstatic or ascetic, it is almost what we would term "rational." Most groups reject continuing revelation because it goes off the deep end, being completely emotional/sensual or rejecting the senses altogether. The Gospel of Mary says no, God will speak to you in your ordinary day in ways you can understand.
The Gospel of Mary seems like a very Quakerly text, actually, because of this emphasis on rational continuing revelation, as well as an emphasis on equality of all people (Mary can teach the male disciples), and Mary also becomes silent because it is out of the silence that the Savior speaks to her. But more on these later.
I wish we had the whole text!!!