(ז) לֹ֥א תִשָּׂ֛א אֶת־שֵֽׁם־יְהוָ֥ה אֱלֹהֶ֖יךָ לַשָּׁ֑וְא כִּ֣י לֹ֤א יְנַקֶּה֙ יְהוָ֔ה אֵ֛ת אֲשֶׁר־יִשָּׂ֥א אֶת־שְׁמ֖וֹ לַשָּֽׁוְא׃ (פ)
https://judaism.stackexchange.com/questions/38426/what-does-it-mean-to-take-gods-name-in-vain
(1) לשוא IN VAIN — for no valid reason, idly. What is a שבועת שוא, an oath taken for no valid reason? If one takes an oath declaring something, the nature of which is evident, to be different from what it is: e. g., swearing about a stone pillar that it is of gold (Shevuot 29a).
https://judaism.stackexchange.com/questions/38426/what-does-it-mean-to-take-gods-name-in-vain
...וראוי ומחיב עלינו בזכרנו שמו הגדול על מעשנו ועל דבורינו לזכרו באימה, ביראה, ברתת ובזיע, ולא כמהתלים ומדברים בדבר קל, כמו הדברים ההווים ונפסדים ואינם נשארים בקיומם כמונו אנחנו בני אדם ושאר דברי העולם השפל.
And it is fitting and obligatory upon us when we mention His great name upon our actions and upon our words, to mention it with fear, with awe, with trembling and perspiration; and not like those that joke and speak about something light, such as the things that exist and perish and do not continue to exist - like us people, and the other things of the lowly world.
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).

