Tafsir of As-Saffat 37:99

(To where He has commanded me, or to where I will withdraw for His worship.) He, Majestic and Exalted, made the going to the place He commanded him to go a 'going to Him,' as is the case with going to a place where one worships Him. This is not a matter of an elliptical construction (i.e., not implying an added word). The intended place is Greater Syria (al-Sham), and it is also said to be Egypt. It is as if the intent is to manifest despair of their faith and an aversion to remaining among them—that is: "I am departing from you and migrating from you to my Lord."

"(He will guide me)"

(To that which contains the righteousness of my religion, or to my objective.) The seen (س) is for the confirmation of the occurrence in the future, because it is in opposition to lan (لن), which confirms negation, as Sibawayh mentioned. Upon him be peace, he was decisive in his statement because of a preceding promise from Him, the Exalted, of guidance when He commanded him to go, or due to the intensity of his, upon him be peace, reliance [upon God], or because it was based on the habit of the Exalted toward him.

If it is asked: Why did Moses, upon him be peace, not say the like of this, but rather said: "Perhaps my Lord will guide me to the sound way" (al-Qasas: 22), using the form of expectation?

It is said: Because there was no preceding promise and no prior habit, and his station required the observance of etiquette with the Exalted, such that he would not speak decisively about a matter before its occurrence, prioritizing this over the observance of intense reliance. The stations of the Prophets vary, and all of them are exalted. It is also said: Because Moses, upon him be peace, said what he said before his mission (prophethood), while Abraham, upon him be peace, said it after his. It is also said: Because Abraham was intent upon a religious matter, so decisiveness was appropriate for him, whereas Moses was intent upon a worldly matter, so lack of decisiveness was appropriate.

Among the strange interpretations is what has been said—to which Qatadah leaned—that Abraham’s, upon him be peace, intention in his saying "Indeed, I am..." was not migration, but rather meeting God, the Exalted, after the burning, thinking he would die in the fire if he were thrown into it, and he intended by "He will guide me" guidance to Paradise. This view is refuted by his prayer for a child, where he said...