How should Christians respond when people use God's name as a curse word?

The third commandment forbids taking God's name in vain (v.11). This may be done seriously or flippantly. One may seriously swear by God that he will do a certain thing, and then not do it. People are so irresponsible that such things become commonplace to the point of then using God's name flippantly, so that they don't care how offensively they talk. But God is not mocked: He will execute judgment on all who are ungodly, not only for their ungodly deeds, but for "all the harsh things which ungodly sinners have spoken against Him" (Jude 15).

Nor is it only Jews then, but professing Christians now, that show themselves as indifferent to the Lord's authority as if He had never thus solemnly uttered His mind. Among Protestants there is some little care to avoid profanity by adopting light and foolish exclamations, or by repeating heathen terms derived from their Greek or Latin reading, forgetting that if the idols are nothing, the demons behind them are real and evil. Romanists are much less scrupulous. It is sad to think how perverts go farther in excuse for their blasphemous phrases than those born and bred in their vain superstitions.

(V. 12). The Apostle has warned us against impatience in the presence of wrongs that would seek to revenge the wrongs in forgetfulness that “the Judge stands before the door.” By thus taking our case into our own hands we may fall into condemnation (verse 9). Now he warns us that there is another way in which we may forget God and come under condemnation. In complaining against men, we may forget the presence of God; but also in defending ourselves we may so forget what is due to God that we seek to confirm our statements by irreverently invoking the Name of God, or heaven, or earth. It is the utmost irreverence, in the heat of passion, to use divine Names to seek to gain credit before men. The Apostle therefore says, “Above all things, my brethren, … let your yea be yea; and your nay, nay.”

"Thou shalt not take the name of the Lord thy God in vain." Alas, from the heart of man, among other evils, comes profanity. The Father's name was ever on our Lord's lips, but never in a light way. He taught and practised in absolute perfection that petition, "Hallowed be Thy name." So also in the performance of vows: none had ever fulfilled their obligations and promises to God. Therefore our Lord warned them against taking oaths which they could not keep (Matt. 5:33-37). But He could say, "Thy vows are upon Me, O God" (Ps. 56:12); "I will pay My vows unto the Lord now in the presence of all His people" (Ps. 116:14). What vows they were! — to glorify God about sin; to seek and to save the lost; to lay deep, firm and broad the eternal foundations of redemption; to bring many to glory. As we contemplate the cost of performing these vows, may we adore Him who never made a rash vow, nor broke a single engagement entered into with His God and Father.

(4) He proceeds now to another matter, in which again what was tolerated under the law is now forbidden in the new morality which He is enforcing. "Thou shalt not forswear thyself, but shalt perform unto the Lord thine oaths," plainly speaks of vowing. There had been great abuse of it, as Israel's history makes manifest: men not hesitating to vow recklessly to God at the dictate of their pride and passion and self-will, to find themselves then entangled by what seemed now their duty. Careless profanity had come in at the heels of this, and God's name been profaned by light appeals to it on every occasion; modified by conscience or the lack of it, by every kind of circumlocution and indirect expression of what they dared not openly give utterance to.

In Ephesians 5:3-6 we have serious instructions about our Christian behavior and conversation. Making puns with the Word of God is a hateful and sinful habit. Slang expressions are most unbecoming in a Christian. Let your speech be always with grace, seasoned with salt (Col. 4:6).

The Lord alone can give you wisdom and grace to act in the painful circumstances you describe. If you really wait on Him, He will teach you when to speak and when to keep silence. There is danger of speaking in haste of temper rather than in a spirit of love, when replying to the godless remarks of the unconverted. This is to be guarded against. Further, we must remember there is very often far more powerful testimony in solemn and dignified silence than in talking for talking's sake. But the Lord will guide the lowly dependent heart. He will tell you when to speak and when to be silent. Then, you may rest assured, the speaking and the silence will each be fruitful in its season.

It would be well if the Christians in China would learn a lesson from the Apostle Paul in their use of this holy name. How often one's heart is made sad by the light and careless way in which even Christians use this precious name, without the title that Paul so loves to use, LORD JESUS.

It appears the Jews had a special reverence for the name, Jehovah, so much so that they would not allow the name to pass their lips. They substituted for it Elohim or Adonai, according to the vowel points by which it was accompanied. Smith’s Concise Dictionary of the Bible affirms that the true pronunciation of the name, Jehovah, by which God was made known to the Hebrews, has been entirely lost through the Jews scrupulously avoiding its use. Would that we, Christians, showed more reverence when we take the sacred name of God upon our lips!

"Hallowed be Thy name." Grace must not be presumed upon. He who has brought us wondrously near to Himself is our Creator and God. The deepest reverence becomes us in our every thought of Him, and with unshod feet we should draw near into His presence.