The Quran

118

وَعَلَى الثَّلاثَةِ الَّذينَ خُلِّفوا حَتّىٰ إِذا ضاقَت عَلَيهِمُ الأَرضُ بِما رَحُبَت وَضاقَت عَلَيهِم أَنفُسُهُم وَظَنّوا أَن لا مَلجَأَ مِنَ اللَّهِ إِلّا إِلَيهِ ثُمَّ تابَ عَلَيهِم لِيَتوبوا ۚ إِنَّ اللَّهَ هُوَ التَّوّابُ الرَّحيمُ

Muhammad Asad

And [He turned in His mercy, too,] towards the three [groups of believers] who had fallen prey to corruption,¹ until in the end-after the earth, despite all its vastness, had become [too] narrow for them and their souls had become [utterly] constricted - they came to know with certainty that there is no refuge from God other than [a return] unto Him; and thereupon He turned again unto them in His mercy, so that they might repent: for, verily, God alone is an acceptor of repentance, a dispenser of grace.²

Or: "had been left behind", i.e., at the time of the expedition to Tabuk. My rendering of alladhina khullifu as "those who had fallen prey to corruption" is based on the tropical meaning of the verb khalufa or khullifa, "he was [or "became"] altered [for the worse]", or "he became corrupt" in the moral sense (see Asas, Nihayah, Lisan al-Arab, Qamas, Taj al-'Arus). This interpretation of alladhina khullifu - applying, in the above context, to those who remained behind under false pretences - has the support of some of the most outstanding Arab philologists, e.g., 'Abd al-Malik al-Asma'i (as quoted by Razi in his commentary on verse 83 of this surah ). - As regards "the three who had fallen prey to corruption", the clasical commentators assume that it is a reference to three persons - namely, Ka'b ibn Malik, Mararah ibn ar-Rabi' and Hilal ibn Umayyah (all of them from among the ansar) - who abstained from the campaign and were thereafter ostracized by the Prophet and his Companions until the revelation of the above verse. But while it is historically established that these three Companions were indeed among the believers who thus failed in their duty (the relevant Traditions will be found in extenso in Tabari's and Ibn Kathir's commentaries on this verse), it seems to me that the context does not warrant such a restriction of its meaning to three particular persons, and that by "the three" are meant three groups of erring believers; (1) those who had advanced equivocal excuses and were thereupon permitted by the Prophet to remain at home (as has been alluded to in verses 43-46 as well as in the first sentence of verse 90); (2) those who absented themselves without permission, but afterwards spontaneously repented their sin (verses 102-105); and (3) those whose cases were at first "deferred" (verse 106), and who repented shortly after the Prophet's return from Tabuk (at which time verse 118 was revealed).
In its wider implication - as contrasted with a purely historical allusion - the above verse relates to all believers who temporarily deviate from the right path and then, after having realized - either spontaneously or in consequence of outside reprobation - that they had "fallen prey to corruption", sincerely repent their sin.