Comentario citado sobre Malaquías 3:5

נפש כי תחטא ושמעה קול אלה, “If a person will sin, having heard a sound (demand) for an oath, etc.” Tanchuma Vayikra 7, commenting on this introduction writes as follows: “take note that when both the creatures in the celestial regions and the ones in the terrestrial regions were created their creation was the result of G’d employing only one half of His name, i.e. Isaiah 26,4 כי ביה ה' צור עולמים, ‘that the Lord employed only the letters י-ה of His name when creating the universe.’ He did so in order that the sinners should not become guilty of desecrating His entire name when sinning.” Observe the sequence of the wording of the Torah in our verse. Instead of the Torah writing אדם כי יקריב מכם לה’ קרבן, the Torah writes אדם כי יקריב מכם קרבן לה'. The reason that the name “for the Lord” appears only at the end is to prevent the possibility of someone dying after having uttered the words “for the Lord” without his being able to complete the sentence. This is how careful one has to be not to utter the name of the Lord in vain.
This attitude is reflected in Solomon writing in Kohelet 5,1 “be not rash with your mouth, and let not your heart be hasty to utter a word before G’d.” Our sages (Tanchuma Vayikra 7) said that Jews should not be rash with offering vows and they should not make a practice of uttering oaths (even true ones). .hey tell of a king called Har in whose time 2,000 towns were destroyed all because of a true oath, because the oath was not called for. What was the oath all about? A person (not just one) swore an oath to his friend that he would go to a certain place and eat and drink there. He completed the journey and kept his oath. All the towns in which they confirmed all their intentions by phrasing them as an oath were ruined. If this is what happened to towns whose inhabitants honoured their oaths, how much worse is in store for people who do not honour their oaths! When in the future, G’d will judge people, the ones who will be accused for swearing a false oath will be put in the same company as the witches, sorcerers, and adulterers. This is all based on Maleachi 3,5: “But I will step forward to contend against you and I will act as a relentless accuser against those who have no fear of Me; who practice sorcery, commit adultery, who swear falsely, who cheat labourers of their hire and who subvert the cause of the widow.” G’d said: “the mouth which I gave you was meant to be used to sing My praises. Instead you use it to defame Me.” This is what is meant by Solomon in Proverbs 16,4: “the Lord made everything for a purpose, for His sake.” Another verse commenting on this subject is found in Isaiah 57,20: “but the wicked are like the troubled sea which cannot rest, whose waters toss up mire and mud.” Just as the waves of the sea in their arrogance rise higher and higher only to collapse upon themselves and be broken as soon as they hit the sand along the shore and the wave following it does not learn a lesson from the fate of the preceding wave, so the wicked do not learn from the fate which has befallen other wicked people before by becoming penitents. This is why they are compared to the waves of the sea which do not know the meaning of ever coming to rest in the world. The righteous, on the other hand, do know the meaning of calm and quiet as testified by Jeremiah 30,10 who writes: “and Yaakov shall again have calm and quiet with none to trouble him.”

ושמעה קול אלה, “by having heard an oath demanding him to testify, and having ignored it;” all the other paragraphs distinguish between inadvertently committed sins and those committed deliberately except the one involving an oath, known as שבועת בטוי, “a futile oath,” which is automatically considered as the one who uttered it doing so while aware of its implications. Solomon confirmed this in Kohelet 5,5 when he said: אל תתן את פיך לחטיא את בשרך ואל תאמר לפני המלאך כי שגגה היא, למה יקצוף האלוקים על קולך וחבל את מעשה ידיך, “do not let your mouth bring you in disfavour; and do not plead before the messenger (angel) that it was only an error; but fear the Lord else He may be angered by your talk and destroy your possessions.” When G–d will sit in judgment of all of His creatures, He will place such people next to the sorcerers and adulterers, as we know from the prophet Malachi (Malachi 3,5) והייתי עד ממהר במשפים ובמנאפים ובנשבעים (בשמי) לשקר, “I will act as relentless accuser against those that have no fear of Me, who practice sorcery, commit adultery and who swear falsely (using My name).”

“If a person incurs guilt, when he heard a public imprecation” [5:1]. The Midrash writes. The Holy One created heaven and earth, the angels and people, everything that was on the earth. The Holy One created this with half a name, which is called YH. Why did the Holy One not create them with a whole name, expecting not to mention the whole name? From here we should learn how the evildoers always mention the name of the Holy One in vain. Our sages say that a person should not swear often, even about the truth. A story happened in the land, Mountain of the King. It contained two thousand cities that were destroyed because of true oaths. That is to say, even when he had sworn truthfully. When someone swore that he wanted to go to Babylon and he went and fulfilled his oath, yet the two thousand cities were destroyed because they always mentioned the [divine] name needlessly. How much more so when a person swears falsely, does the Holy One punish him? The Holy One will punish those who swear falsely along with the people, who engage in sorcery and engage in illicit sexual relations, as the verse says, “I will step forward to contend against you, and I will act as a relentless accuser against those who have no fear of Me; who practice sorcery, who commit adultery, who swear falsely” [Malachi, 3:5].²⁰Tanhuma, Vayikra, 7. Cited in Bahya, Leviticus, 5:1.