Tafsir of Az-Zukhruf 43:50

"But when We removed from them the punishment" (that is, through his supplication; thus, there is an omission in the discourse: "So he supplicated to Us to remove the punishment, and We removed it from them"), "behold, they break [their word]."

"Behold" indicates that the breaking of their covenant took them by surprise regarding their guidance, or that they were surprised at the time of breaking their covenant. Abu Haywah recited "yankithun" with a kasra (vowel 'i') under the letter kaf.