The homily on the Avar siege of Constantinople in 626 attributed to Theodore Syncellus shares numerous linguistic features both with Theodore’s homily of 623 on the Virgin’s Robe and with George of Pisidia’s poem of 626/7 on the siege. Theodore and George both celebrate the combined efforts of Patriarch Sergius and the Virgin Mary in saving the city, but Theodore also highlights the involvement of other agents, in particular the patrician Bonus and the young Heraclius Constantine, who were jointly in charge of the city while Emperor Heraclius was campaigning against the Persians. The homily is structured around the exegesis of three Old Testament passages: the promise in Isaiah 7 to King Ahaz about the salvation of Jerusalem; the analysis of numbers in Zachariah 8.19; and God’s destruction of Gog and Magog in Ezekiel 38–39.