Matthew 1:23, refers to the prophecy written in Isaiah 7:14, glossing the name Immanuel (Emmanuel, עמנואל) as "God with us":
Ἐμμανουήλ: ὅ ἐστιν μεθερμηνευόμενον "Μεθ᾽ἡμῶν ὁ θεός"
Emmanuel, which being interpreted is, God with us. (KJV)
Nobiscum Deus in Latin, Μεθ᾽ἡμων ὁ Θεός (Meth himon o theos) in Greek, was a battle cry of the late Roman Empire and of the Eastern Roman Empire.
It is also a popular hymn of the Eastern Orthodox Church, sung during the service of Great Compline (Μεγα Αποδειπνον). The Church Slavonic translation is С Hами Бог (S Nami Bog).
It was used for the first time in Germany by the Teutonic Order. In the 17th century, the phrase Gott mit uns was used as a 'field word', a means of recognition akin to a password, by the army of Gustavus Adolphus at the battles of Breitenfeld (1631), Lützen (1632) and Wittstock (1636) in the Thirty Years' War. In 1701, Frederick I of Prussia changed his coat of arms as Prince-Elector of Brandenburg. The electoral scepter had its own shield under the electoral cap. Below, the motto Gott mit uns appeared on the pedestal.
Съ нами Богъ!" S nami Bog! was used as a motto by the Russian Empire.