Thou shalt not take the name of the Lord thy God in vain
"Thou shalt not take the name of the LORD thy God in vain" (KJV; also "You shall not make wrongful use of the name of the Lord your God" (NRSV) and variants, Biblical Hebrew: לֹא תִשָּׂא אֶת-שֵׁם-יהוה אֱלֹהֶיךָ לַשָּׁוְא, romanized: Lōʾ ṯiśśāʾ ʾeṯ-šēm-YHWH ʾĕlōhēḵā laššāwəʾ) is the second or third (depending on numbering) of God's Ten Commandments to man in Judaism and Christianity. Exodus 20:7 and Deuteronomy 5:11 read: Thou shalt not take the name of the LORD thy God in vain; for the LORD will not hold him guiltless that taketh his name in vain.
Source: Wikipedia — Thou shalt not take the name of the Lord thy God in vain (CC BY-SA 4.0)