How was the Prophet afraid of the Hour suddenly commencing in his time, despite the non-completion of its signs, which would require many long years?

Allah concealed the knowledge of the Hour from all His creation and did not reveal its appointed time to His Prophet, but rather revealed to him its signs.

It is mentioned in some hadiths that the Prophet, peace be upon him, stood up in alarm, fearing that the Hour might occur during a solar eclipse. Scholars have responded to this with several answers: 1. That Abu Musa assumed that, and his assumption is not necessarily correct. 2. It is probable that he had not been revealed all the signs of the Hour at that time. 3. He might have feared that the eclipse was a precursor to the major signs of the Hour that would follow it.

Al-Nawawi and Al-Sindi summarized these answers, emphasizing that the Prophet's alarm, peace be upon him, might have been due to the narrator's assumption, or because this eclipse occurred before he was informed of all the signs of the Hour, or out of fear that the eclipse was one of its precursors.