The first and the second verse both mentioned two crimes committed by disbelievers. They took Halal as Haram and made the Haram become Halal for themselves by themselves. The third verse (34) describes their sad end and the punishment they would have in the Hereafter. It was said:
وَلِكُلِّ أُمَّةٍ أَجَلٌ ۖ فَإِذَا جَاءَ أَجَلُهُمْ لَا يَسْتَأْخِرُونَ سَاعَةً ۖ وَلَا يَسْتَقْدِمُونَ
(And for every people there is an appointed time. So, when their appointed time comes, they will not be late for a moment, nor will they go before).
In other words, what is being said here is that those committing excesses who, despite their contumacy, are basking in the sunshine of the blessings of Allah Ta` ala, and do not seem to be anywhere close to being punished, they should not lose sight of the customary practice of Allah that He, in His infinite mercy, keeps granting a long leash to sinners so that they would somehow stop doing what they do. But, the term of this leash and the time of this respite stands determined in the ultimate knowledge of Allah Ta` ala. When that time comes, it just comes - neither too late nor too soon. Thus, criminals are caught in punishment. At times, the punishment descends right here in this world - and if, the punishment does not visit them here, it waits to receive them soon after their death.
As for the appointed time not being late or early as stated in this verse, it is a manner of saying, something like saying to a salesperson in a store: at is your last price, more or less? It is obvious that the inquiry is for the lower price, not the higher. But, it is put there as a subordinate suffix. Similarly, the real objective here is to state that there will be no delay after the appointed time. The mention of ` before' along with ` late' makes it closer to common comprehension.