The Ten Commandments were carved on two tablets. The Sages explain that the arrangement of the commandments opposite one another was of great significance.

How were the commandments given? The first five were carved on this tablet and the latter five were carved opposite the first five on that tablet. It is written on the first tablet: “I am the Lord your God” (Exodus 20:2), and it is written opposite it on the second tablet: “You shall not murder” (20:13). The verse thereby teaches that concerning anyone who sheds blood, the verse ascribes blame to him as though he diminishes the image of God, the King. This can be explained through a parable to a flesh and blood king who entered a region and established icons of himself, and crafted idols of himself, and minted coins of himself. After a while, the people there bent his icons, smashed his idols, invalidated his coins, and diminished the image of the king. So too, concerning anyone who sheds blood [of a person, who is created in the image of God], the verse ascribes him blame as though he diminishes the image of God, the King, as it is stated: “One who sheds the blood of man…as He made man in the image of God” (Genesis 9:6). It is written on the first tablet: “You shall have no other gods before Me” (Exodus 20:3), and it is written opposite it on the second tablet: “You shall not commit adultery” (20:13). The verse teaches that concerning anyone who engages in idol worship, thereby choosing another god, the verse ascribes him blame]as though he commits adultery against the Omnipresent. It is written on the first tablet: “You shall not take the name of the Lord your God in vain” (20:7) when taking an oath, and it is written opposite it on the second tablet: “You shall not steal” (20:13). The verse teaches that anyone who steals ultimately comes to take an oath in vain. It is written: “Remember the Sabbath day, to keep it holy” (20:8), and it is written opposite it: “You shall not bear false witness against your neighbor” (20:13). The verse teaches that anyone who profanes the Sabbath testifies before He who spoke and the world came into being that He did not create His world in six days and did not rest on the seventh, and anyone who observes the Sabbath testifies before He who spoke and the world came into being that He created His world in six days and rested on the seventh…. It is written: “Honor your father and your mother” (20:12), and it is written opposite it: “You shall not covet” (20:14). The verse teaches that anyone who covets will ultimately beget a son who curses his father and his mother, and will honor one who is not his father. That is why the Ten Commandments were given with five carved on this tablet and five carved corresponding to them on that tablet. (Mekhilta deRabbi Yishmael, Yitro, Mesekhta deBaĥodesh 8)