Tafsir of Hud 11:25

Then, He, the Exalted, began mentioning the stories of the prophets who invited [people] to Allah, the Exalted, and clarifying their conditions with their nations, so that the Prophet—may Allah's peace and blessings be upon him—would increase his resolve in [his] mission and bear the opposition he faced from the stubborn ones. Thus, the Almighty said: "(And We certainly sent Noah to his people)."

The waw (and) is ibtida'iyyah (initiating), and the lam is situated as the answer to an implied oath. Its particle is estimated as ya' (oath particle), not waw, even if the latter is more common, so as to avoid the gathering of two waws. Others estimate it as a waw and do not mind that.

Noah, according to the famous account, is the son of Lamech, son of Methuselah, son of Idris, peace be upon them. He is the first prophet sent after him [Idris]. Ibn Abbas—may Allah be pleased with them both—said: He was sent, peace be upon him, at the turn of forty years of his age, and he remained inviting his people for the duration Allah related—one thousand years except fifty years—and he lived after the Flood for sixty years, making his age one thousand and fifty years. Muqatil said: He was sent when he was one hundred years old. It is also said: fifty, and it is said: two hundred and fifty. He remained inviting his people for the duration He, the Glorified, related, and he lived after the Flood for two hundred and fifty years, making his age one thousand four hundred and fifty years.

"(Indeed, I am for you a warner)"—[read with the kasra] based on the intended meaning of speech, i.e., "he said," or "as one saying." Ibn Kathir, Abu Amr, and al-Kisa'i read it with a fatha based on the elision of a preposition, meaning: "clothed/involved in that speech," which is "Indeed, I am for you a warner." When the preposition was elided, it was opened just as it was opened in ka'anna (as if), and the meaning remains that of the kasra, similar to your saying: "Indeed, Zayd is like the lion," based on the view that ka'anna is a compound and not a particle in its own right. There is no departure from the third person to the second person in this, contrary to Abu Ali.

Perhaps the limitation to mentioning his status—peace be upon him—as a "warner" is because they did not seize the spoils of his—peace be upon him—glad tidings.

"(Clear)"—meaning: clarifying for you the causes of punishment and the way of salvation from it.