When we say “Spirit” in relationship to Pentecost, there’s a one-track hive mind for that. Of course we’re referring to the Holy Spirit, the Third Person of the Triune Godhead. We’re speaking of the God who pours Herself out on the people of God, loosening their tongues in proclamation, their hearts in love, and their hands in generosity to one another and turning “the Other” into “another.” The Pentecostal Spirit brings forth the Church and reveals the Son of God in her midst.
By contrast, “the Spirit of Christmas” has a delightful ambiguity. Some people mean the core of the celebration: the incarnation of the Son of God. Then there’s those referring to some sense of spirit of generosity, charity, goodwill towards men, yada, yada, yada…and then there’s the lovely tradition of telling ghost stories at Christmas (somewhat forgotten in the 21st century), or the three ghosts from A Christmas Carol. The point is, range of meaning here is wild and about as chaotic as your grandmother’s house at Christmas dinner.
But if you pay attention to the appointed readings (and I don’t know a church of any tradition that doesn’t have a liturgical commitment to the Nativity Gospels and the Isaiah predictions of the Son of God’s birth), the Holy Spirit is very much involved in Christmas. We hear the her voice all over the place, inspiring Joseph’s vision and commissioning angelic witnesses. We see the birth of the Son of God, whose conception was accomplished in Mary by the hovering Spirit of God. We see Mary pondering these things that happen in her heart, a gift of the Holy Spirit who causes God’s people to remember His mighty deeds. And, to this day, we see the Spirit of God bringing all these things to our remembrance–to reveal Jesus, to set us to proclaiming, loving, and sharing generously to one another (And making “the Other” into “another”). The Spirit of Pentecost is the Spirit of Christmas, grounded in the flesh and blood of the Christ child.