وَلَمْ يَكُنْ مَانِعٌ مِنَ الْعَطْفِ
There must also be no impediment to coordination.
Even apparently related sentences should not be joined if wāw creates a false grammatical dependency or makes one speaker’s assertion appear to belong to someone else.
Example: If one clause quotes a person's speech and the next gives the narrator's own comment, ill-placed coordination may wrongly attribute the comment to the quoted speaker. Later cases of fasl illustrate exactly this problem.