The Sabbath became the most effective patron and protector of the Jewish people. All through the Middle Ages they led an existence almost like that of slaves. Even now not all of this has disappeared. But when the Sabbath candles are lightened, the Jew in the Ghetto threw away all the toil of his daily life. All insult was shaken off. God's love, which once more brought him the Sabbath on every seventh day, also brought back to him, in his lowly hut, his honor and his human rights.
Even today the scholars dispute -- in self-mockery and ignorance -- what in the last instance could have effected the continuance of the Jews. They do not want to acknowledge the truth of the unique God as the final reason for it. They prefer to make the law responsible for it. They think that they are at the same time able to despise the latter because of its legalistic formality and lack of inwardness.
However, the Sabbath is the most genuine and most intimate representative of the law. And through the Sabbath the law, in accorance with the unique God who loves men, has preserved Judaism as well as the Jews....
Hermann Cohen, Religion of Reason out of the Sources of Judaism, p. 158.