There are some tantalizing clues. He was named Abraham, for his grandfather, Abraham, who died when Lincoln’s own father was quite young; his paternal great-great-grandfather was named Mordecai, as was his uncle.
Their last name derives from the city from which they emigrated, Lincoln in England (many Jews adopted as family names the city they hailed from). The city of Lincoln, it is interesting to note, is famous for being home to one of England’s oldest and most important Jewish communities, as well as for saving its Jews during the 12th century Crusader riots. However, Abraham Lincoln’s son Robert denied that his family was of Jewish ancestry, saying that his father was merely jesting when he spoke with Rabbi Wise.
Still, it is not so hard to believe that Lincoln, who never professed a faith other than citing the Ten Commandments in Exodus, saw himself as a descendant of Jewish tradition, for where did his sense of justice and fairness come from if not from Mosaic law, or his belief that a mere amendment to the Constitution would do more than an army to win a war?