"They ask you about the Hour, when is its arrival?" meaning: When is its occurrence?
Muhammad said: It is also said that the meaning is: When will He bring it about? Because it is proceeding toward a limit. It is said: A thing is said to "rasa" (arrive/settle) when it becomes fixed.
﴿يَسْأَلُونَكَ عَنِ السَّاعَةِ أَيَّانَ مُرْسَاهَا﴾ مَتَى قِيَامُهَا؟
قَالَ محمدٌ: وَقِيلَ: الْمَعْنَى: مَتَى يَبْعَثُهَا؛ لأَنَّهَا جاريةٌ إِلَى حدٍّ، وَيُقَالُ: رَسَا الشَّيْءُ يَرْسُو؛ إِذَا ثَبَتَ.
