(No nation can advance their term, nor can they delay it.) means, they are taken at the appropriate time, as decreed by Allah in His Book that is preserved with Him, before they were created, nation after nation, century after century, generation after generation, successors after predecessors.
ثُمَّ أَرْسَلْنَا رُسُلَنَا تَتْرَى
(Then We sent Our Messengers in succession.) Ibn `Abbas said, "(This means) following one another in succession." This is like the Ayah:
وَآوَيْنَاهُمَا إِلَىٰ رَبْوَةٍ ذَاتِ قَرَارٍ وَمَعِينٍ (and We gave them shelter on a height, a place of rest and running springs). According to Bayan-ul-Qur’ an, this verse refers to the event that a tyrant was resolute to kill Sayyidna ` Isa and his mother (علیہما السلام) right from his childhood. They escaped from him and, with Allah's grace, found a place on a height where they enjoyed a peaceful life until Sayyidna ` Isa (علیہ السلام) attained maturity and was entrusted with prophethood. (This commentary is taken from Khulasa-e-tafsir of Ma` ariful-Qur’ an).
Tazkirul Quran
Maulana Wahiduddin KhanOn ayahs 41–43
The declaration of truth for which a prophet of God makes his appearance is the most serious reality of this world. But the prophet announces this reality only in the form of reasoning. The real believers are those who recognise the truth at a rational level and surrender themselves to it. When a group conclusively proves that it is not capable of recognising the Truth in the form of reasoning, God reveals the Truth in the form of a blast (saihah). The Truth becomes such a loud roar that nobody has the strength to face it. But, when this stage is reached, i.e. when Truth appears in the shape of the roar, it is the hour of retribution and not an opportunity for the acceptance of the Truth. All that is left for man to do then, is to repent and pay for his foolishness for all eternity. For, despite seeing, he was blind, and despite hearing, he was dumb to the voice of Truth.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.