Exodus 31

Exodus 31:15

Ambrose of Milan: They were also commanded to keep the holiday of the Sabbath one day in the week, so as to be subjected to no burthen, and I would that being thus released from earthly works they had escaped, carrying with them to that perpetual sabbath of future ages the burthen of heavy crimes. But as God knew how prone to fall the people were, He enjoined a part upon the weaker by the observance of one day, He reserved the fulness for the stronger: the Synagogue observes the day, the Church immortality. In the Law therefore is a part, in the Gospel is perfection. — Letter 74.5

Bede: Indeed by the fleshly sabbath, which was kept according to the letter, the people were ordered to keep free from all servile work on the seventh day. [The meaning of] the spiritual sabbath, in the light of the sevenfold spiritual grace which we have received, is that we should remain on holiday from the unrest of vices not only on one day but every day. For if, according to the Lord’s voice, “Everyone who commits sin is a servant of sin,” it is clear that sins are properly understood as servile works, and we are ordered to walk free of them, as it were on the seventh day, in the partaking of spiritual grace. [We are ordered] not only to keep from wrong deeds but also to devote ourselves to good deeds. — Homilies on the Gospels 1.23

Exodus 31:18

Augustine of Hippo: This law was “written with the finger of God,” and this finger of God the New Testament explicitly identifies with the Holy Spirit. For when one Evangelist has “By the finger of God, I cast out devils,” another says this same thing thus: “By the spirit of God, I cast out devils.” Who would not have this joy in the divine mysteries, when the redemptive doctrine shines with so clear a light, rather than all the powers of this world though they be infused with unwonted peace and happiness? — LETTER 55

Augustine of Hippo: Let us look at the Decalogue itself. Undoubtedly Moses received on the mount a law to be ministered to the people, written on tables of stone by the finger of God. It is comprised in ten commandments, among which there is no charge of circumcision or of the animal sacrifices which by Christians are no longer offered. In these ten commandments, apart from the observance of the sabbath, I would ask what the Christian is not bound to observe. Of the commands, not to make or worship idols or any other gods but the one true God, not to take God’s name in vain, to honor parents, to avoid fornication, murder, theft, false witness, adultery, and the coveting of that which is another’s—which among these commands can be said not to bind the Christian? What the apostle calls “the letter that kills” is not this law, written on the two tables, but that of circumcision and the other ancient ordinances now done away. For in the law of the tables comes “You shall not covet,” the command by which (says Paul), “though it is holy and righteous and good, sin deceived me and thereby slew me”8—which can only be “the letter killing.” — ON THE SPIRIT AND THE LETTER 14.23