[1.] When we assert a thing, without implying this condition that ought to be contained in it, if God will, or he be pleased to enable us to do it. This the apostle particularly mentions, when he blames those who say, To day or to morrow we will go to such a city, and continue there a year, and buy, and sell, and get gain. Whereas they know not what shall be on the morrow. And therefore, they ought to say, If the Lord will, we shall live, and do this, or that, James iv. 13, 15.
[2.] When we promise a thing, that is out of our power to perform; and, much more, when we do not design to perform it.
[3.] When we promise a thing, which is in itself unlawful; as the Jews did, who bound themselves under a curse, that they would not eat nor drink till they had killed Paul, Acts xxiii, 12. If we have obliged ourselves by an oath, to perform that which is unlawful, as we sin in making, we should do so in fulfilling it. There are, however, some cases in which persons may not perform what they have sworn to do, and yet not be guilty of perjury, or violation of their oaths; as,
1st, When they have used their utmost endeavours to fulfil what they have promised to do, but yet cannot accomplish it. Though here it must be observed, that if the thing promised was absolutely out of their power when the promise was made, the oath (as we but now observed) was unlawful. But supposing the thing was in their power when they promised it; but an unforeseen providence has put it out of their power at present, though they have used their utmost endeavours to perform it, they are not chargeable with the guilt of perjury.
2dly, If we have promised to do a thing that is for the advantage of another; but now see reason to alter our mind, apprehending some detriment will accrue thereby to ourselves; we must, notwithstanding, fulfil our promise. Thus the Psalmist says, he sweareth to his own hurt, and changeth not, Psal. xxv. 4. However, if the person to whom we have made the promise, who is to receive the advantage by our fulfilling it, is willing to discharge us from our obligation, we may omit to do it, and not be guilty of perjury.
Here it might be enquired; whether we are always obliged to fulfil a promise extorted from us by violence? In answer to which, it is generally supposed, by divines, that we are not. Nevertheless, the person can hardly be excused from sin in snaking such a promise, when he designs not to perform it, though some small degree of force or threatening were used; especially since the will cannot be obliged to consent, or the tongue to utter the promise. And to all this we may add, that they are guilty of the breach of this Commandment (how much soever they may think themselves guiltless) who use equivocations, or mental reservations, in taking solemn and religious oaths. Thus the Papists make no scruple of swearing to support the government under which they live, and yet take the first opportunity that offers to subvert it, pretending they swore to support it as it stood before the reformation; or when they swear allegiance to their sovereign, and yet do what they can to dethrone him; and have this mental reservation, that they intended only to do it for the present, till they have a convenient opportunity to join in a successful rebellion. By this means they break through the solemn tie of religious oaths, elude the law, and impose upon the common sense of mankind, in such a way, as even the Heathen themselves are afraid and ashamed to do.
(3.) This farther leads us to consider this Commandment as broken by swearing profanely; namely, when we make use of the name of God, and pretend to confirm what we assert by an appeal to him, and, at the same time, are far from doing this in a religious manner. This many do, who give vent to their passions by profane swearing, by invoking the name of God upon light and trifling occasions, without that due regard that ought always to be paid to his divine Majesty.
Under this head we may observe, that cursing is a vile sin, whether a man imprecates the wrath of God on himself or others. They who curse themselves, do, in effect, pray that God would hasten their everlasting destruction; as though their damnation slumbered, or as if it were a thing to be wished for. These do that which the devils themselves would not venture to do. And to curse others is to put up a profane wicked prayer to God, to pour out his vengeance upon them, which is the highest affront to him; as though the vials of his wrath were to be emptied on men, when they pleased, to satisfy their passionate revenge against them. This also includes in it a vile instance of uncharitableness, towards those whom we are commanded to love as ourselves, Matt. xxii. 39. And how contrary is it to that golden rule laid down by our Saviour, All things whatsoever ye would that men should do to you, do ye even so to them? chap. xvii. 12. Thus we are said to break this Commandment by perjury or profane swearing. And to this we may add, that it is notoriously broken by sinful vows; either when we resolve, or determine, to do what is unlawful, or bring ourselves under solemn engagements, to do that which is lawful, to our own strength, without dependance on the grace of God in Christ.
(4.) It is farther observed in this answer, that men take the name of God in vain, by sinful lots; but this is to be farther explained. Therefore let it be considered; That when lots were an ordinance by which God, in an extraordinary manner, determined things that were before unknown; they being an instituted means of appealing to him for that end; as in the case of Achan and others, Josh. vii. 13, 14. Acts i. 26. then lots were not to be used in a common way, for that would have been a profaning a sacred institution. But since this extraordinary ordinance is now ceased, it does not seem unlawful, so as to be an instance of profaneness, to make use of lots in civil matters; [[213]] provided we do not consider them as an ordinance which God has appointed, in which we think we have ground to expect his immediate interposure; and to depend upon it as though it were a divine oracle. In this view it would be unlawful at present, to use lots in any respect whatsoever.
(5.) Persons are said to break this Commandment by murmuring, quarrelling at, curiously prying into, and misapplying God’s decrees or providences, or perverting what he has revealed in his word, i. e. when we apply things sacred to profane uses, and have not a due regard to the glory of God, which is contained therein; when we pervert scripture, by making use of those sacred expressions that are contained therein, in our common discourse, as some make the scripture the subject of their profane wit and drollery. This is certainly a taking God’s name in vain. And, it is farther added, that we do so, by maintaining false doctrines, i. e. when we pretend, that such a doctrine is from God, when it is not, or that he makes himself known hereby; when the doctrine is altogether disowned by him.