The commandment against taking God's name in vain is often read as a rule about cursing. The Targum Pseudo-Jonathan sees something far more grave. "My people of the house of Israel, Let no one of you swear by the name of the Word of the Lord your God in vain; for in the day of the great judgment the Lord will not hold guiltless any one who sweareth by His name in vain" (Exodus 20:7).
Two Targumic additions transform the verse. First, the Targum replaces the Lord with the Word (Memra) of the Lord — an Aramaic circumlocution that captures the active, speaking presence of God in the world. To swear falsely is not to abuse a label; it is to misuse a living Name.
Second, the Targum specifies when the reckoning comes: the day of the great judgment. This is eschatological language. Earthly courts may fail to catch a liar. Human witnesses may be fooled. But the yom ha-din ha-gadol, the great final judgment, is the court no one escapes. The Targumist warns: you may get away with it here. You will not get away with it there.
Why is this sin so serious? Because a false oath in God's name weaponizes the holiest thing in existence to cover a lie. Every other form of deception damages a relationship. This one corrupts the very concept of truth.
The takeaway: the Name of God is not a prop to win arguments — it is the scaffolding of the world. Bend it with a lie and you crack the beams holding everything up.