"Rather, you thought that the Messenger and the believers would never return to their families, ever." The hypocrites used to say: Muhammad will never return to Medina, ever. "And you were a people ruined," meaning: corrupt.
Muhammad said: "Al-Bur" (ruin) in some dialects means: corrupt. It is said: "Their deeds became 'bura'"—that is, void; and "their dwellings became 'bura'"—that is, desolate and ruined.
Interpretation of Surah al-Fath from verse 14 to verse 15.
﴿بَلْ ظَنَنْتُمْ أَنْ لَنْ يَنْقَلِبَ الرَّسُولُ وَالْمُؤْمِنُونَ إِلَى أَهْلِيهِمْ أَبَدًا﴾ كَانَ المُنَافِقُونَ يَقُولُونَ: لن يرجع مُحَمَّد إِلَى الْمَدِينَة أبدا ﴿وَكُنْتُمْ قَوْمًا بورا﴾ يَعْنِي: فاسدين.
قَالَ محمدٌ: البور فِي بعض اللُّغَات: الفاسدُ، يُقَال: أَصبَحت أَعْمَالهم بورًا؛ أَي: مُبْطَلة، وأصبحت ديارُهم بورًا؛ أَي: معطلة خرابا.
تَفْسِير سُورَة الْفَتْح من الْآيَة ١٤ إِلَى آيَة ١٥.