How many calls to prayer are there for Fajr, and does the phrase "prayer is better than sleep" remain beneficial if Muslims are gathered in the mosque, and is there a hadith related to this matter, or is saying that considered an innovation?

There were two calls to prayer (adhan) for Fajr prayer during the time of the Messenger of Allah, peace and blessings be upon him: The first was before Fajr, to make the one who was praying at night return [to sleep] and to awaken the one who was sleeping. The second was at the beginning of the time [of Fajr], to announce its entry and to call to prayer. The majority of scholars are of the opinion that the phrase "Prayer is better than sleep" is said in the second adhan, and the muezzin must be careful to say it, even if people are already in the mosque, due to the benefits it contains and its reminder of the truth that "Prayer is better than sleep." Muslims also benefit by repeating it after the muezzin, as the Prophet, peace and blessings be upon him, said: "When you hear the muezzin, say as he says." Women, children, Muslim jinn, and those who are drowsy in the mosque may also benefit from it. Therefore, this Sunnah should be preserved and not abandoned.