This has been clarified further in the third verse (53) where it was said that once the hypocricy of the hypocrites has been exposed and the reality behind their claims and oaths of friendship comes out in the open, Muslims would wonder if those were the people who used to assure them with sworn claims of their friendship and there they were all ruined as everything they did just to pretend had gone to waste. That Allah Jalla Sha'nuhu has mentioned the conquest of Makkah and the disgrace of the hypocrites in these verses was something which everyone saw only after a few days with their own eyes.
- 5:5353
وَيَقُولُ الَّذِينَ آمَنُوا أَهَٰؤُلَاءِ الَّذِينَ أَقْسَمُوا بِاللَّهِ جَهْدَ أَيْمَانِهِمْ ۙ إِنَّهُمْ لَمَعَكُمْ ۚ حَبِطَتْ أَعْمَالُهُمْ فَأَصْبَحُوا خَاسِرِينَ
Then the believers will say: "Are these the people who had sworn by God on solemn oath and said: "We are surely with you?" Wasted have been all their deeds, and losers they remain.
- common.revelation-Medinan
- common.hizb : 47