(ז) לֹ֥א תִשָּׂ֛א אֶת־שֵֽׁם־יְהוָ֥ה אֱלֹהֶ֖יךָ לַשָּׁ֑וְא כִּ֣י לֹ֤א יְנַקֶּה֙ יְהוָ֔ה אֵ֛ת אֲשֶׁר־יִשָּׂ֥א אֶת־שְׁמ֖וֹ לַשָּֽׁוְא׃ (פ)
(7) You shall not swear falsely by the name of the Eternal your God; for the Eternal will not clear one who swears falsely by His name.
You shall not bring up the name of YHWH, your God, for a falsehood, because YHWH will not make one innocent who will bring up His name for a falsehood.
Another reason why using God's name to make a lie believable is out of the question is because by doing so the person swearing the oath loses his צלם אלוקים, the image of God he has been created with and is known by. Such a person will become known instead as שוא, vain, false, worthless. God's name is "truth." Anyone associating that name with a lie, makes the name of God "fly away," seeing the person doing so has chosen something vain. An apt translation of this verse would be: "do not remove from yourself the name of the Lord your God on account of the pursuit of something that is vain, worthless."
Ex 20:7. bring up His name for a falsehood. (Traditionally translated “take His name in vain.”) This does not mean that one cannot say the divine name in an exclamation—much less does it mean saying the words “God” or “Lord” in an exclamation. It refers to falsehood. The term refers to a false report (Exod 23:1) and a false witness (Deut 5:17; which corresponds to the term “lying witness” here in Exod 20:13). This commandment means that one cannot make an oath in God’s name and not fulfill it. To appreciate the seriousness of this commandment, note the case of Joshua, who is deceived by the Gibeonites into making an oath of nonaggression. When Joshua learns that the Gibeonites are among the Canaanite residents whom he was commanded by God to destroy, he lets them live, disobeying a direct command from God rather than violate one of the Ten Commandments (Joshua 9). And note the case of Jephthah, who makes an oath to sacrifice the first thing to come out of his gate, which turns out to be his daughter. He sacrifices her rather than violate this commandment (Judges 11). (It is not reckoned legally as murder. Human sacrifice is forbidden, but it is legally distinguished from murder, which involves malice.) As horrible as this is (especially in light of the Aqedah), it conveys the seriousness of this commandment and of the principle that the Ten Commandments outweigh other laws.
This baraita is apparently self-contradictory. On the one hand, you said that one who recites havdala in the Amida prayer is more praiseworthy than one who recites havdala over the cup of wine, indicating that reciting havdala in the Amida prayer alone is sufficient. And then it is taught: If one recited havdala in this, the Amida prayer, and that, over the cup of wine, may blessings rest upon his head. And since he fulfilled his obligation to recite havdala with one, he is exempt, and the additional recitation of havdala over the cup of wine is an unnecessary blessing. And Rav, and some say Reish Lakish, and still others say Rabbi Yoḥanan and Reish Lakish both said: Anyone who recites an unnecessary blessing violates the biblical prohibition: “Do not take the name of the Lord your God in vain” (Exodus 20:7).
לא תשא את שם, “do not utter the sacred name, etc.” Seeing that you have not ever seen a visual image of God, you can obviously not utter an oath by invoking someone else as a deity. Even so, you must not even swear an oath in His name unless there is an absolute necessity to do so, as God does not allow His sacred name to be used for profane reasons, or for secular purposes. This is one sin which will not be subject to being wiped out even by repentance, i.e. כי לא ינקה, “He will not consider such a person as being free from guilt.”
לשוא, “in vain.” Do not make a habit of prefacing any parts of your speech by invoking the name of God (unless as a pseudonym), even if what you say is the truth. The very habit of uttering God’s name on too many occasions will lead you to do so when it is a blasphemy, or an outright lie. If that were to happen it would result in an unforgivable sin, i.e. כי לא ינקה.
לא תשא. Even a king of flesh and blood insists on not lending his good name to something criminal or dishonourable. How much more so is the Creator of the entire universe entitled to have His Holy Name respected! We must remember that the existence of the Lord our God, i.e. His eternal existence, is not comparable to any other existence in this universe. This awareness must be reflected whenever we utter His Name, something that must be accompanied by feelings of awe and reverence. One does not use His Holy Name in light-hearted conversation. It is not appropriate to bring God's Name into conversations which deal with transient matters. Needless to say that it is even less appropriate to associate His name with lies and cheating.


