the Chaldeans into pieces. During his sojourning in Canaan, Abraham was accustomed to extend hospitality to travelers and strangers and taught how to praise God also knowledge of God to those who had received his kindness. Along with Isaac and Jacob, he is the one whose name would appear united with God, as God in Judaism was called Elohei Abraham, Elohei Yitzchaq ve Elohei Ya'aqob ("God of Abraham, God of Isaac, and God of Jacob") and never the God of anyone else. He was also mentioned as the father of thirty nations. Abraham is generally credited as the author of the Sefer Yetzirah, one of the earliest extant books on Jewish mysticism. According to Pirkei Avot, Abraham underwent ten tests at God's command. The Binding of Isaac is specified in the Bible as a test; the other nine are not specified, but later rabbinical sources give various enumerations. Christianity In Christianity, Abraham is revered as the prophet to whom God chose to reveal himself and with whom God initiated a covenant (cf. Covenant Theology). Paul the Apostle declared that all who believe in Jesus (Christians) are "included in the seed of Abraham and are inheritors of the promise made to Abraham." In Romans 4, Abraham is praised for his "unwavering faith" in God, which is tied into the concept of partakers of the covenant of grace being those "who demonstrate faith in the saving power of Christ". Throughout history, church leaders, following Paul, have emphasized Abraham as the spiritual father of all Christians. Augustine of Hippo declared that Christians are "children (or "seed") of Abraham by faith", Ambrose stated that "by means of their faith Christians possess the promises made to Abraham", and Martin Luther recalled Abraham as "a paradigm of the man of faith." The Roman Catholic Church, the largest Christian denomination, calls Abraham "our father in Faith" in the Eucharistic prayer of the Roman Canon, recited during the Mass. He is also commemorated in the calendars of saints of several denominations: on 20 August by the Maronite Church, 28 August in the Coptic Church and the Assyrian Church of the East (with the full office for the latter), and on 9 October by the Roman Catholic Church and the Lutheran Church–Missouri Synod. In the introduction to his 15th-century translation of the Golden Legend's account of Abraham, William Caxton noted that this patriarch's life was read in church on