Tafsir of As-Saffat 37:88

Meaning: He contemplated in a specific manner regarding their states. In reality, this was of the same style as the contemplation of those who are perfect in observing the creation of the heavens and the earth and reflecting upon it, as this is what befits him, peace be upon him. However, he made them believe that he was contemplating their states—such as conjunctions, oppositions, and other configurations which, according to their claims, indicate future events—so that he might base upon this act what would lead him to his goal, which served as a means to rescue them from the state they were in.

The apparent meaning, after taking into account this illusion, is that it was an illusion of contemplating the rulings of the horoscope of his birth, peace be upon him, according to what their claims suggested regarding the configurations that had newly emerged for him at that time. This is a form of "deceptive action" (ma'arid al-af'al), similar to what occurred in the story of Joseph, peace be upon him, when he searched the bags of his half-brothers before the bag of his full brother. For the searcher began with their bags while knowing that the beaker was not in them, and he delayed searching his brother's bag while knowing that it was indeed in it, in order to feign that he did not know in which bag it was, thereby negating any accusation against himself had he begun with his brother’s bag.