"And it is not for amusement," meaning: not a lie.
Muhammad said: "Al-Raj'" (the returning) in language refers to rain; it was named as such because it comes, returns, and recurs.
﴿وَمَا هُوَ بِالْهَزْلِ﴾ بِالْكَذِبِ.
قَالَ مُحَمَّد: (الرجع) فِي اللُّغَةِ: الْمَطَرُ سُمِّيَ بِذَلِكَ، لِأَنَّهُ يَجِيء وَيرجع ويتكرر.
