Verse 33 says, “Again, you have heard that it was said to the ancients: You shall not perjure yourself, but you shall render to the Lord what you have sworn.” This is the old law regarding swearing.
In verses 34 through 36 we see the Lord’s new law regarding swearing: it is not to swear at all. The new law of the kingdom forbids the kingdom people to swear in any manner, by the heaven, by the earth, by Jerusalem, or by their head, because the heaven, the earth, Jerusalem, and their head are not under their control, but under God’s. We should not swear by either the heaven or the earth, for they are not ours. Likewise, we should not swear by Jerusalem because, as the city of the great King, it is not our territory. We should not even swear by our head because we “cannot make one hair white or black.” All these things—heaven, earth, Jerusalem, and even the hairs of our head—are not under our control. We are nobody and we control nothing.
In verse 37 the Lord says, “But let your word be, Yes, yes; No, no; for whatever is more than this is of the evil one.” The kingdom people’s word needs to be simple and true: “Yes, yes; No, no,” not convincing others with many words. Our words should be brief and clear. Those who are honest do not talk very much. But beware of talkative people: they may be liars. Liars are very talkative, always giving many reasons and excuses for things. But an honest person is usually brief. Furthermore, we must realize that much talk in the presence of God does not make the Lord happy. When we go to the Lord, we must go to Him in honesty, saying things to Him in a brief way.
In verse 37 the Lord says that whatever is more than a straight yes or no is of the evil one. Here we come to a crucial point: in our talking the evil one may be present. When we speak more words than are necessary, those words are not of us, but of the Devil, the evil one. This indicates that in our talking the evil one is with us. This is especially true in married life. Although we may not talk that much with others, it is easy for there to be excess talk between a husband and wife. If you want to avoid a poor marriage, let there be no loose talk between you and your husband or wife. Be on the alert! While you are talking, the evil one may be with you. This is not my word; it is the word of the Lord. The Lord’s word in this verse is a strong indication the evil one is seeking the opportunity to express himself through our excessive talking. Do not say too much. Simply say as much as is needed. Do not go any further. If you go further than is necessary, the evil one will be expressed. If you follow this advice, you will be a very happy husband or wife. However, if you talk too much, you will have difficulty. This will open the shaft of the bottomless pit and allow the demons to come out. We should learn to speak only what is necessary. Never try to convince others by many words. Such convincing words are not reliable; rather, they are falsehoods that come from the evil one.
Now we come to the third law changed by the Lord, the law regarding the resistance of evil. Verse 38 says, “You have heard that it was said, An eye for an eye, and a tooth for a tooth.” This is the old law.