In the old days, this used to be the feast of Christ's circumcision, on the octave day of his birth.
One of the things I still retain somewhat, and miss in its more robust form, is the shape that the Church gave to time, to the year. Advent, Christmas, Epiphany, Lent and Easter, Pentecost, and all the ranks of saints, and fasts, and sacred moments that moved in complex parallel. Dense with the ebb and flow of ancient images and stories, grown up over centuries, with the Old and New covenants intersecting in layers of text and type. By contrast, the post-Christian calendar of the New Religion is thin, rational and commercial when it is not merely parasitic or dishonest.
I have visited the chapel in Rome where Christ's foreskin was once venerated, il Santo Prepucio, in ages when, despite their reputation, people were more comfortable with the body and its ways than our weirdly Puritan and promiscuous times. When the mad Dominican mystic Catherine of Siena was espoused to Jesus in the 14th century, he gave her his foreskin as a wedding ring.
Religious. Not spiritual.