Allah states that the foremost of the close believers are a multitude, a crowd among the earlier generations and a few from the latter generations. There is a difference over the meaning of the first generations and the later generations. Some said that the former means earlier (believing) nations, while the later refers to this Ummah. This was reported from Mujahid and Al-Hasan Al-Basri, in the collection of Ibn Abi Hatim, and this is the preference of Ibn Jarir. He considered it supported by the saying of Allah's Messenger ﷺ:
(We are the later nation, but the foremost on the Day of Resurrection.) Ibn Jarir did not mention any other interpretation nor did he attribute this view to anyone else. There is another Hadith that could support this meaning. Imam Abu Muhammad bin Abi Hatim recorded that Abu Hurayrah said that when these Ayat were revealed,
وَلَحْمِ طَيْرٍ مِّمَّا يَشْتَهُونَ (and the meat of birds that they desire....56:21]. It is recorded in a Prophetic Tradition that the inmates of Paradise will get meat of whatever birds they desire, as and when they desire it.
Tazkirul Quran
Maulana Wahiduddin KhanOn ayahs 26–39
The group at the forefront (as-sabiqun) will comprise of those who, immediately accept the Truth when it appears before them, and surrender themselves to it without hesitation. According to the Prophet’s wife, ‘A’ishah, the Prophet said, ‘Do you know, on the Day of Judgement, who will be the first to find a place in the protective shade of God?’ People said that God and His Prophet knew best. Then he said, ‘It will be those to whom Truth was presented and they accepted it. When Truth was demanded of them, they gave it. They gave the same decision with regard to others as they did with regard to themselves.’ (Tafsir ibn Kathir). In the early period of the call for Truth, for those who came forward and embraced Islam, it was a discovery. The generation coming after them, regarded Islam as a legacy. It is this difference between discovery and legacy which raises the status of first group over that of the second group. Naturally, the second group is larger in number than the first group. In the Hereafter, there will be ordinary rewards for the second group while, for the first group, there will be royal rewards.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.