«فَالْتَزَمَ كُلٌّ مِنَّا قِسْطًا»
So each of us committed himself to a share.
Iltazama, from form VIII, means to undertake an obligation. Qisṭan refers to a portion or allotted share. Kullun minnā makes this a collective commitment rather than the payment of a single rich patron.
The story has reached the moment when one man’s narrative persuades an entire gathering to act together. This line establishes each person’s undertaking, not yet the full performance of every promised payment.