Where does “Christmas is coming” come from?

Christmas is coming (English) comes from English Christmas, from Middle English Cristemasse, from Old English Cristes mæsse, from Old English mæsse, from Vulgar Latin messa, from Latin missa, from Latin missum, from Latin mittō — to hurt; to exchange, remove; to replace, to...

Ancestry of “Christmas is coming”, step by step

Christmas is coming traces back through two separate lines of ancestry.

via English Christmas

StepLanguageWordMeaning
1EnglishChristmasA festival or holiday commemorating the birth of Jesus Christ and incorporating various Christian, pre-Christian, pagan, and secular customs including gift-giving, which in Western Christianity is celebrated on December 25 (Christmas Day) in most places
2Middle EnglishCristemasseChristmas the 25th of December
3Old EnglishCristes mæsseChristmas
4Old Englishmæssemass
5Vulgar LatinmessaEucharist, dismissal; Eucharist; dismissal;...
6LatinmissaMass; Christian eucharistic liturgy; nominative...
7Latinmissumaccusative supine of mittō; inflection of...
8Latinmittōto send, dispatch, cause to go, let go, release, discharge
9Proto-Italicmeitōto put forth, put out
10Proto-Indo-Europeanmeyth₂-to hurt; to exchange, remove; to replace, to...

via English is

StepLanguageWordMeaning
1EnglishisThird-person singular simple present indicative...
2Middle Englishisice; That which is short-lived like ice; icy...
3Old Englishīsice
4Proto-West Germanicīsice
5Proto-Germanicīsąice
6Proto-Indo-Europeanh₁eyH-ice, frost
Every word from Proto-Indo-European meyth₂-Every word from Proto-Italic meitōEvery word from Latin mittō