Exodus 20:7

The thirdcommandment. The name of God to be treated with reverence.

take … in vain properly, take up (viz. upon the lips, as Exodus 23:1; Psalms 15:3; Psalms 16:4) … for unreality (Di. -zur Nichtigkeit") i.e. make use of it for any idle, frivolous, or insincere purpose. The root idea of shâw", is what is groundlessor unsubstantial: hence in a material sense it means unreal, vain(Psalms 60:11); and in a moral sense it denotes what is empty, frivolous, or insincere: cf. Exodus 23:1 -Thou shalt not take up a groundlessreport"; Psalms 24:4 -hath not lifted up his soul (i.e. directed his desires) unto unreality" (i.e. to what is either frivolous or insincere): in the Psalms it is generally rendered vanity, but it often really means what we should call insincerity, as Psalms 12:3; Psalms 41:6 (see the Glossary in the writer's Parallel Psalter, p. 464). God's name is to be treated with reverence; it is not to be desecrated either by false swearing (Leviticus 19:12 (H), Jeremiah 5:2; Jeremiah 7:9; Zechariah 5:4; Malachi 3:5), or by being used disrespectfully for any other frivolous or idle purpose, as in cursing or reviling, or to support false pretensions of being able to use magic or divination, or to predict the future (Jeremiah 27:15).

hold … guiltless i.e. leave unpunished, as 1 Kings 2:9 shews is implied and as the word is sometimes actually rendered, e.g. Proverbs 6:29 Jeremiah 25:29. Cf. Jeremiah 34:7, with the note.