You are reading a tafsir for the group of verses 28:85 to 28:88

The Prophet’s cause is in every way God’s cause. Prophethood is voluntarily given to him by God without any request on his part. Throughout his entire existence he remains steadfast in adhering to the Truth. He is appointed to announce the plain, unvarnished Truth, even if it is unpleasant to people. He is destined to reach his appointed goal and no impediment shall bar his path. After the Prophet, the same will hold true for those who rise, in conformity with the Prophet, as missionaries of Truth. To the extent that they resemble the Prophet in conduct, they will go on being entitled to succour promised by God to His prophets in His Book.