This commandment involved many things for Israel. What it taught was a reverence for God and the name of God. It did prohibit cursing or blasphemy using God’s name, but it also included flippant or trite uses of His name also. Good Lord, God bless, thank-you Jesus, Lord have mercy, and many other common uses of God’s names today—when used irreverently or without any regard for God’s being—would have brought stoning in Israel’s day. The name of Jehovah was so reverenced that Jewish scribes would use a new pen every time it was written. This command also taught respect for God and for God’s authority—including parental, governmental, and religious leaders. There was no ridiculing or jokes made about God, the President, men of God, or any other person of divine prominence.

Exo 20:7 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.

Psa 89:7 God is greatly to be feared in the assembly of the saints, and to be had in reverence of all them that are about him.

Lev 24:10 And the son of an Israelitish woman, whose father was an Egyptian, went out among the children of Israel: and this son of the Israelitish woman and a man of Israel strove together in the camp;
11 And the Israelitish woman's son blasphemed the name of the LORD, and cursed. And they brought him unto Moses: (and his mother's name was Shelomith, the daughter of Dibri, of the tribe of Dan:)
12 And they put him in ward, that the mind of the LORD might be shewed them.
13 And the LORD spake unto Moses, saying,
14 Bring forth him that hath cursed without the camp; and let all that heard him lay their hands upon his head, and let all the congregation stone him.
15 And thou shalt speak unto the children of Israel, saying, Whosoever curseth his God shall bear his sin.
16 And he that blasphemeth the name of the LORD, he shall surely be put to death, and all the congregation shall certainly stone him: as well the stranger, as he that is born in the land, when he blasphemeth the name of the LORD, shall be put to death.

Acts 23:1 And Paul, earnestly beholding the council, said, Men and brethren, I have lived in all good conscience before God until this day.
2 And the high priest Ananias commanded them that stood by him to smite him on the mouth.
3 Then said Paul unto him, God shall smite thee, thou whited wall: for sittest thou to judge me after the law, and commandest me to be smitten contrary to the law?
4 And they that stood by said, Revilest thou God's high priest?
5 Then said Paul, I wist not, brethren, that he was the high priest: for it is written, Thou shalt not speak evil of the ruler of thy people.

Exo 21:17 And he that curseth his father, or his mother, shall surely be put to death.

While grace certainly teaches reverence for God and authority, this command has a deeper meaning for those in Christ. In examining the word vain we find that it means something that is empty, put-on, or without any real value. Those outside of Christ seek God and use His name in vain because they have no real relationship with God; their piety, works, and worship of Him are empty, artificial, and without spiritual value. Jesus constantly berated the religious hypocrites of His day telling them that “in vain they do worship” God. To others He said, “Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven.” To all those who vainly worship God, He will tell them in that great day of judgment, “I never knew you: depart from me, ye that work iniquity.”

Matt 15:7 Ye hypocrites, well did Esaias prophesy of you, saying,
8 This people draweth nigh unto me with their mouth, and honoureth me with their lips; but their heart is far from me.
9 But in vain they do worship me, teaching for doctrines the commandments of men.

Matt 7:21 Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven.
22 Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works?
23 And then will I profess unto them, I never knew you: depart from me, ye that work iniquity.

To those in Christ, grace teaches us to be real about our relationship with God. We are no longer under the law or any external demand that we try to appear righteous or religious before God. We no longer have to live in a vain show about what we are pretending to be. We no longer have to pretend to be righteous—we are righteous in Christ. We must therefore not be hypocritical about our relationship with God. God requires openness and honesty, especially from His children. When we talk to God, we need to express our real feelings and problems. God is not going to condemn us for being honest. God also requires a heartfelt worship from His children. The vain show of spirituality that many Christians put on in Church and before the world is not the worshipping of God, but the proud display of the flesh. Many times those who pray in church, who sing, or say amen and praise the Lord, are doing it to attract attention to themselves. God is worshiped more by what we do for His glory than by our playing church. A child of God who knows in their heart that their fellowship with God is phony or non-existent is breaking this third commandment. They need to re-establish what is the ground of their relationship with God and start to be real in their worship of Him.

Heb 9:14 How much more shall the blood of Christ, who through the eternal Spirit offered himself without spot to God, purge your conscience from dead works to serve the living God?

1 Cor 15:10 But by the grace of God I am what I am: and his grace which was bestowed upon me was not in vain; but I laboured more abundantly than they all: yet not I, but the grace of God which was with me.

John 4:23 But the hour cometh, and now is, when the true worshippers shall worship the Father in spirit and in truth: for the Father seeketh such to worship him.
24 God is a Spirit: and they that worship him must worship him in spirit and in truth.

James 1:26 If any man among you seem to be religious, and bridleth not his tongue, but deceiveth his own heart, this man's religion is vain.
27 Pure religion and undefiled before God and the Father is this, To visit the fatherless and widows in their affliction, and to keep himself unspotted from the world.

Isa 1:13 Bring no more vain oblations; incense is an abomination unto me; the new moons and sabbaths, the calling of assemblies, I cannot away with; it is iniquity, even the solemn meeting.
14 Your new moons and your appointed feasts my soul hateth: they are a trouble unto me; I am weary to bear them.
15 And when ye spread forth your hands, I will hide mine eyes from you: yea, when ye make many prayers, I will not hear: your hands are full of blood.
16 Wash you, make you clean; put away the evil of your doings from before mine eyes; cease to do evil;
17 Learn to do well; seek judgment, relieve the oppressed, judge the fatherless, plead for the widow.