[A spring therein, named Salsabil]. Salsabil is the name of the spring.
Muhammad said: The meaning is: (They are given to drink of a spring, Salsabil). The Arabs used to find ginger palatable and would use it as a proverb in combination with wine; so God addressed them with what they knew and desired in the world. He says: You shall have in the Hereafter the like of what you desire in the world if you believe. Salsabil in the language is an attribute for a place that is the ultimate in smoothness, and it was indeclinable (sarifa) because it is the end of a verse. Interpretation of Surah al-Insan from verse (19-22).
﴿عينا فِيهَا تسمى سلسبيلا﴾ السَّلْسَبِيلُ: اسْمُ الْعَيْنِ.
قَالَ مُحَمَّدٌ: الْمَعْنَى: (يُسْقَوْنَ عَيْنًا سَلْسَبِيلًا)، وَكَانَتِ الْعَرَب تستطيب الزنجيل، وَتَضْرِبُ بِهِ الْمَثَلُ وَبِالْخَمْرِ مُمْتَزِجِينَ، فَخَاطَبَهُمُ اللَّهُ بِمَا كَانُوا يَعْرِفُونَ وَيَسْتَحِبُّونَ فِي الدُّنْيَا، يَقُولُ: لَكُمْ فِي الْآخِرَةِ مِثْلُ مَا تَسْتَحِبُّونَ فِي الدُّنْيَا إِنْ آمَنْتُمْ، وَالسَّلْسَبِيلُ فِي اللُّغَةِ صِفَةٌ لِمَكَانٍ غَايَةٍ فِي السَّلامَةِ وَصُرِفَ؛ لِأَنَّهُ رَأْسُ آيَة. تَفْسِير سُورَة الْإِنْسَان من آيَة (١٩ - ٢٢)