Yigdal is a metrical Hebrew hymn of thirteen lines, each summarising one of the Thirteen Principles of Faith that Moses Maimonides set out in the twelfth century, the existence, unity and incorporeality of God, his eternity, that he alone is to be worshipped, prophecy, the supremacy of Moses, the divine origin of the Torah, its immutability, God's knowledge of human deeds, reward and punishment, the coming of the Messiah, and the resurrection of the dead. Composed, most likely, by a fourteenth-century Italian liturgical poet to render Maimonides' creed in singable verse, it is sung at the opening or close of services in many communities and is among the most familiar of synagogue hymns. It represents a notable instance of dogma set to music: the nearest thing in Judaism to a credal statement, cast in a form the whole congregation can sing, so that the principles of the faith are affirmed in praise. Like Adon Olam, with which it is often paired, it has been set to numerous melodies.
Maimonides himself set out his thirteen principles in prose as part of his commentary on the Mishnah, intending them as the minimum required beliefs for a Jew in good standing, a controversial claim in its own right since Judaism had not previously articulated a fixed dogmatic creed in that form; Yigdal's achievement was to compress that prose argument into singable verse without significant loss of content. The hymn's authorship is most often assigned to Daniel ben Judah of Rome, though the attribution rests on manuscript evidence that is not entirely conclusive, and some older sources proposed other candidates.