Tafsir of Ghafir 40:41

If you ask: Why did he repeat the calling of his people? And why did the waw (conjunction "and") appear in the third call but not the second?

I say: As for the repetition of the call, it serves to increase their alertness and awaken them from the slumber of heedlessness. It also reflects that they are his people and his kin, and they are in a state that will lead to their ruin. He knows the path to their salvation, and advising them is his duty. He grieves for them, treats them with gentleness, and seeks through this to ensure they do not suspect his motives—for their joy is his joy, and their sorrow is his sorrow—so that they might accept his counsel. This is similar to how Abraham (peace be upon him) repeated his advice to his father: "O my father."

As for the inclusion of the waw (conjunction), the second call introduced a statement that was an explanation and clarification of what was previously summarized; thus, it took on the ruling of the preceding statement, which precludes the use of the waw. The third call, however, introduces a statement that does not hold that same status. It is said: "He called him to such-and-such" and "He called him for it," just as you say: "He guided him to the path" and "He guided him for it."

{Of which I have no knowledge} Meaning: regarding His divinity. The negation of "knowledge" here is intended to negate the "known object." It is as if he said: "You associate with Him that which is not a god," and how can that which is not a god be known as a god?

{Assuredly, that to which you invite me has no claim in this world or in the Hereafter; and that our return is to Allah, and that the transgressors are the companions of the Fire. You will remember what I say to you, and I entrust my affair to Allah. Indeed, Allah is Seeing of [His] servants.}