وَيَصْنَعُ ٱلْفُلْكَ وَكُلَّمَا مَرَّ عَلَيْهِ مَلَأٌ مِّن قَوْمِهِۦ سَخِرُوا۟ مِنْهُ ۚ قَالَ إِن تَسْخَرُوا۟ مِنَّا فَإِنَّا نَسْخَرُ مِنكُمْ كَمَا تَسْخَرُونَ
Wa yasn'ul fulka wa kullamaa marra 'alaihi malaum min qawmihee sakhiroo minh; qaala in taskharoo minnaa fa innaa naskharu minkum kamaa taskharoon
And he was building the ark, and whenever the chiefs of his people passed by him, they mocked him. He said, "If you mock us, we will mock you just as you mock,
Yaṣna'u is a continuous form and kullamā means every single time, so the mockery is spread across the whole length of the build, a passer-by at a time. Nuh's answer defers everything and names no argument: the mocking will change hands, and the following verse says when. Obedience looks like this — carrying on with an instruction whose point stays invisible to everyone watching.