Tafsir of Surah At-Tawba 9:118
﴿وَعَلَى الثَّلَاثَةِ الَّذِينَ خُلِّفُوا حَتَّىٰ إِذَا ضَاقَتْ عَلَيْهِمُ الْأَرْضُ بِمَا رَحُبَتْ وَضَاقَتْ عَلَيْهِمْ أَنفُسُهُمْ وَظَنُّوا أَن لَّا مَلْجَأَ مِنَ اللَّهِ إِلَّا إِلَيْهِ ثُمَّ تَابَ عَلَيْهِمْ لِيَتُوبُوا إِنَّ اللَّهَ هُوَ التَّوَّابُ الرَّحِيمُ﴾
Translation of the meaning
And [He also forgave] the three who were left alone [i.e., boycotted, regretting their error] to the point that the earth closed in on them in spite of its vastness and their souls confined [i.e., anguished] them and they were certain that there is no refuge from Allāh except in Him. Then He turned to them so they could repent. Indeed, Allāh is the Accepting of Repentance, the Merciful.
English Translation - Noor International Center — v1.1.2 · QuranEnc.comThe words of the two imams are given in their original Arabic, verbatim, with references.
Imam Ibn al-Qayyim
قد فسرها كعب بالصواب، وهو أنهم خلفوا من بين من حلف لرسول الله صلى الله عليه وسلم، واعتذر من المتخلفين«زاد المعاد في هدي خير العباد» 3/518