93. Yusuf Ali remarks: “(These words have)… two significations, both implied in this passage: (1) those who give no evidence that is false; and (2) those who do not assist at anything which implies fraud or falsehood.”
The textual Zur is to believe in the goodness of a thing while it is otherwise. Hence the varying explanations offered by the Salaf as meaning Shirk (sin of association), music, or falsehood. (Ibn Jarir)
One report from Ibn `Abbas has it that the allusion is to the festivities of the polytheists (Qurtubi). Abu al-`Aliyyah, Ta’us, Ibn Sirin, Dahhak, Rabi` b. Anas and others have also held the same opinion. (Ibn Kathir)
False testimony is one of the many possible connotations. A report preserved in the Sahihayn and quoted by Ibn Kathir says the Prophet asked, “May I not tell you of the greatest of the great (sins)?” He said that three times. Those present said, “Sure do, O Messenger of Allah.” He said, “To declare partners to Allah and to mistreat the parents.” Then he straightened himself up from the reclining position and said, “Lo! It is false testimony (Zur). Lo! It is false testimony.” He kept repeating until the Companions wished he would stop.
94. Al-laghw is every word, or deed, that is of no profit to anyone, which, if the believers happen to encounter, they skirt themselves away from it. Therefore, some of the Salaf have included, by implication, sex talks in al-laghw in which the believers do not indulge, but rather, leave the company graciously (kiraam). However, sometimes passing by in kiraam might involve an action. For example, if they see an undesirable act, they forbid it, or when they see an unlawful act being carried out, they prevent it, using force if required. (Ibn Jarir).
Ibn Abi Hatim reported that, once, Ibn Mas`ud passed by a futile thing but did not pause. The Prophet remarked, “Ibn Mas`ud turned a karim” (Ibn Kathir).