﴿وَلَا تَمْنُنْ تَسْتَكْثِرُ﴾
Do not confer a favor while regarding what you give as great. (Al-Muddaththir 74:6)
Here tastakthiru is an affirmative imperfect that can be explained as the attendant state of the action expressed by lā tamnun. It follows without a circumstantial wāw. The wāw at the beginning of the verse is not an introductory wāw to tastakthiru; its syntactic position and function are different.