As regards the dating of Matthew JC Fenton points out that Matthew frequently refers to "their" [the Jews] synagogues. This suggests a date after 85 CE since that's when Christians were kicked out of the Jewish meeting places. Matthew also has a strong anti-Jewish flavor which suggests the this split had already taken place. Matt 22:7 may be a reference to the destruction of the Temple which would place it after 70 CE. On the flip side the Gospel is alluded to by Ignatius so it's no older than 110 CE.
If God wanted us to be Atheists we'd be born that way.
