"So that they might turn back, disappointed." Muhammad said: Regarding His saying "a portion," he means: a segment. Regarding His saying "or suppress them," it is said: the root of it is "yakbuduhum" (to afflict their livers); meaning: to strike them in their livers with grief and rage. The 'ta' (ت) in it is substituted for the 'dal' (د) due to the proximity of their points of articulation.
﴿فينقلبوا خائبين﴾ قَالَ مُحَمَّد: قَوْله ﴿طرفا﴾ يَعْنِي: قِطْعَة، وَقَوله: ﴿أَوْ يَكْبِتَهُمْ﴾ قيل: الأَصْل فِيهِ: يكبدهم؛ أَي: يصيبهم فِي أكبادهم بالحزن والغيظ، التَّاء مبدلة فِيهِ من دَال؛ لقرب مخرجيهما.