Tafsir of Al-Inshirah 94:7

(So when you have finished) that is, from an act of worship such as conveying the revelation, (then exert yourself) meaning: tire yourself in another act of worship, as a form of gratitude for what We have enumerated for you of the past blessings and what We have promised you of the aforementioned favors. It is as if He, the Almighty and Majestic, when He enumerated for him—may Allah bless him and grant him peace—what He enumerated and promised him what He promised, He stirred him toward gratitude and diligence in worship, so that he would not leave any of his times vacant of it. Thus, when he finished an act of worship, he would follow it with another.