the Sabbath day to keep it holy
Upper left-hand quadrant: Then the hand of the Lord will strike your livestock in the fields - the horses, the asses, the camels, the cattle, and the sheep - with a very severe pestilence. Exod. 9:3
Upper right-hand quadrant: On the one was written, 'Remember the Sabbath day to keep it holy', and opposite it: 'You shall not bear false witness.' Mekhilta According to Rabbi Ishmael.
Lower left-hand quadrant: When Moses went up on high, he found the Holy One busy joining crowns to the letters (of the Torah, and Moses remained respectfully silent). B. Shab 89a
Lower right-hand quadrant: And after R. Yeshevav was slain, they brought out R. Eleazar ben Shammua for execution. The Ten Martyrs