Praise be to Allah.
The word used in the hadeeth is not waqt (= time), but dahr (= time, vicissitudes of time) [this element of confusion may stem from translation of the question into Arabic]. This hadeeth was narrated by Muslim (5827) from Abu Hurayrah.
Other versions of the hadeeth are:
“Do not inveigh against time (al-dahr), for Allaah is time”
“Let not any one of you say, ‘Woe to time,’ for Allaah is time”
“Allaah says, ‘The sons of Adam offend Me and say, Woe to time, but they should not say Woe to time. I am time, I alternate the night and the day, and if I willed, I could seize them both.’”
With regard to the meaning of the hadeeth, al-Nawawi said:
They said: this is a metaphor, because the Arabs used to inveigh against time when disasters such as death, old age, loss of money, etc., happened. They would say, ‘Woe to time’ and other phrases cursing or inveighing against time. So the Prophet (peace and blessings of Allaah be upon him) said: ‘Do not inveigh against time for Allaah is time’, i.e., do not inveigh against the One Who brings about those disasters, for that will be directed towards Allaah, for He is the One Who causes them to happen. Time (al-dahr) means al-zamaan (time) which cannot do anything in and of itself, for it is just one of the things that have been created by Allaah.
The meaning of the phrase “for Allaah is time” means that He is the One Who causes those events and accidents to happen, and He is the Creator of all that happens. And Allaah knows best.
(Sharh Muslim, 15/3)
It should be noted that “time” (al-dahr) is not one of the Names of Allaah; it is attributed to Allaah in the sense that He created it and is controlling it, i.e., He is the Creator of time. Some phrases in the same hadeeth also indicate this, as when He says,“It is in My Hand, I alternate the night and the day.” The One Who alternates and the thing which is alternated cannot be one and the same; there is the One Who alternates – i.e., Allaah – and the thing which is alternated – i.e., time, which Allaah controls as and when He wills.
See: Fataawa al-‘Aqeedah by Shaykh Ibn ‘Uthaymeen, 1/163
Al-Haafiz Ibn Katheer said, in his Tafseer of the aayah (interpretation of the meaning):
“And they say: “There is nothing but our life of this world, we die and we live and nothing destroys us except Ad‑Dahr (time)” [al-Jaathiyah 45:24]
Al-Shaafa'i, Abu ‘Ubaydah and others said, in their commentary on the hadeeth of the Prophet (peace and blessings of Allaah be upon him), “Do not inveigh against time for Allaah is time” – During the Jaahiliyyah, if some difficulty, trial or disaster befell them, the Arabs wouldsay ‘Woe to time’, attributing those events to time and inveighing against it. But the One Who brought those events to pass is Allaah, so it was as if they were inveighing against Allaah, may He be glorified, because in fact He was the One Who caused those things to happen. So it was forbidden to inveigh against time in this manner, because Allaah is Time, i.e., He is the One lWho is controlling it, but the Arabs were attributing those events to Time.
This is the best of the comments made in the Tafseer of this hadeeth, and this is what is meant. And Allaah knows best.
(Tafseer Ibn Katheer, 4/152)
Shaykh Ibn ‘Uthaymeen (may Allaah preserve him) was asked about the ruling on inveighing against time. He replied:
Inveighing against time may be divided into three categories:
1.Where the intention is to convey information without blaming or condemning. This is permissible, such as when a person remarks, “We are suffering from the heat (or the cold) today” and the like, because deeds are judged according to their intentions, and in this case a person is merely describing what is happening without expressing discontent.
2.Where a person inveighs against time as the cause of events, as if by inveighing against it he means that time is what causes things to alternate between good and bad. This is shirk akbar (major form of shirk) because when a person attributes events to something other than Allaah, this means that he believes that there is another creator alongside Allaah.
3.Where a person inveighs against time but believes that the One who causes things to happen is Allaah, but he inveighs against time because of the bad things that happened. This is haraam because it is contrary to the sabr (patience) that is required, but it is not kufr because the person does not inveigh directly against Allaah. If he were to inveigh directly against Allaah, he would be a kaafir.
(Fataawaa al-‘Aqeedah, 1/197)
Other reprehensible expressions which people utter include cursing the hour or the day on which a certain bad thing happened, and so on. This is a sin because it is cursing and improper speech, and because this is cursing something which does not deserve to be cursed. What has the hour or the day done wrong? Nothing apart from the fact that the events happened then, but they are only created things which have no control over anything and cannot be held to blame. If a person inveighs against time, this reflects on the Creator of time. The Muslim should be above speaking in such a foolish and improper manner. And Allaah is the One Whose help we seek.