The Quran

167

وَلِيَعلَمَ الَّذينَ نافَقوا ۚ وَقيلَ لَهُم تَعالَوا قاتِلوا في سَبيلِ اللَّهِ أَوِ ادفَعوا ۖ قالوا لَو نَعلَمُ قِتالًا لَاتَّبَعناكُم ۗ هُم لِلكُفرِ يَومَئِذٍ أَقرَبُ مِنهُم لِلإيمانِ ۚ يَقولونَ بِأَفواهِهِم ما لَيسَ في قُلوبِهِم ۗ وَاللَّهُ أَعلَمُ بِما يَكتُمونَ

Muhammad Asad

and mark out those who were tainted with hypocrisy and, when they were told, "Come, fight in God's cause" - or, "Defend yourselves"¹ - answered, "If we but knew [that it would come to a] fight, we would indeed follow you." Unto apostasy were they nearer on that day than unto faith, uttering with their mouths something which was not in their hearts,² the while God knew fully well what they were trying to conceal:

Only a fight in self-defence - in the widest meaning of this term - can be considered a "fight in God's cause" (see 2: 190-194, and the corresponding notes); and, thus, the particle "or" between these two phrases is almost synonymous with the expression "in other words".
This is an allusion to the three hundred men who, on the way from Medina to Mount Uhud, forsook the Prophet on the specious plea that he did not really intend to give battle (see note 90 above). But since they knew in their hearts that it would come to a fight, their defection from God's cause almost amounted to a denial of Him (kufr, here rendered as "apostasy").