Merry Christmas and Merry Mawlid as “Light Upon Light”:

“He said, “Thus said your Lord, `It is easy for Me. We will render him (Jesus) a sign/revelation (ayah) for mankind , and a mercy from Us. This is a matter decreed.” Holy Qur’an 19:21

As a “sign for mankind”, Jesus Christ’s (as) miraculous birth is celebrated by his followers and the “revelation” he brought (that is, his very self) and the religious traditions he inaugurated are honored throughout the world to this day by both his followers, and the followers of the Prophet Muhammad (saw).
As “a mercy from Us”, he is spiritually present for his followers “here and now” through the Holy Spirt, and shall be present for them, “there and then” as a means of intercession insha’Allah (God-Willing). Similarly the Prophet Muhamamd (saw) is a “Mercy from Us” and is present for us “here and now, through the Baraka Muhammadiya (Muhammadan Blessing) and “there and then” as a means of intercession (shifaa) for Muslims as well as for “all of mankind”, according to certain Prophetic reports.
As a “Word of God” (KalimatuLlah, in the Qur’an), and as “revelation (ayah) for mankind”, Jesus Christ (as) is the Incarnation of the Word and Spirit of/from God. He is the founder of the World’s largest Religion to date, whose Prophecy and religion is honored by the Prophecy of Muhammad (saw) in the Qur’an (which is the “Speech of God”, Kalaam Allah). The Christ (as) is thereby “included” in Muhammad’s Prophecy which for Muslims, completes and seals the cycle of Prophetic Guidance, whose Prophecy has been “sent as a mercy to all worlds”–even “other” religious worlds.
For these reasons, it can only be “Light upon Light” to use Qur’anic metaphor, that the occasions of the celebrations of these two Divinely Revealed Lights coincide at the end of the Solar Gregorian year 2015 and the Lunar Hijri year 1437. And there is “no distinction” between one spiritual light from another spiritual light when they are put together–as they have been put together this year by God’s Decree. As Rumi says:
“If ten lamps are present in one place, each differs in form from the other. Yet to distinguish without any doubt the light of each, when you turn your face toward their light, is impossible….In things spiritual there is no division and no numbers; in things spiritual there is no partition and no individuality.” (Mathnawi verses 678-679 and 681).
So when the two greatest and most influential Prophetic Lights–who have founded and inspired the two largest world religions–eclipse each other and coincide, it can not but create a synergism of Light, or “Light upon Light”: a Light which inwardly is One and indivisible, despite their sacred outwards distinctions.
And this is all “a matter decreed”…
Merry Christmas and Mawlid Mubarik of Sayiduna Isa (as) and Sayiduna Muhammad (saw) to All!