The phrase “But give glad tidings to those who believe and work righteousness (Wa bashshir alladhīna āmanū wa ‘amilū al-ṣāliḥāt):” when the Most High charged the people [with worship], and proved [the Messenger’s] prophethood, and charged the Messenger with conveying His commands – so that by giving the glad tidings [of Paradise] he would ensure they complied with the obligations, which entailed difficulties and the giving up of worldly pleasures – he was commanded both to warn and to convey the good news of Allah the Most High’s pleasure, and His grace, and nearness, and of everlasting happiness.
And the phrase “that theirs are gardens beneath which flow (anna la-hum jannātin tajrī):” as was mentioned above, man’s most essential need, since he has a body, is a place and a dwelling. The most beautiful places are those with plants and trees, and the most pleasant are those with pools among their verdant gardens, and the most splendid are those that have abundant streams flowing among their trees and under their pavilions. This is why it says “beneath which rivers flow.”
After somewhere [to live] man’s greatest need, the finest of physical pleasures, is food and drink. These are indicated by [the words] gardens and rivers. And the finest of sustenance is that which is familiar, so one may appraise the degree of its superiority over similar foods. And the most delicious are fruits, as long as they are varied. And the purest pleasure is from [fruits] that are known and picked from close by. But most delicious of all is knowing that they are the fruits of one’s labours. This is why it says “Every time they are fed with fruits therefrom, they say: ‘Why, this is what we were fed with before.’” That is, in this world or before now.
The phrase “for they are given things in similitude (wa utū bihi mutashābihan):” it says in a Hadith that they will be similar in form but different in taste.1 Hence, the verse indicates that the pleasure of fruits lies in their change and variation, and that perfect pleasure is when the person is served and [the fruit] is given to him.
The phrase “and they have therein companions pure (wa la-hum fī-hā azwājun muṭahharatun):” as you saw above [when describing] the string [for the verse’s pearls], a person needs a wife, a companion, to dwell with, through whose eyes he may look and who may see through his eyes, and whose love he may benefit from, this being the gentlest of the rays of divine mercy. Complete intimacy too is with her.
See, al-Mundhirī, al-Targhīb wa’l-Tarhīb, vi, 296-9; al-Ghazālī, Iḥyā’ ‘Ulūm al-Dīn (Cairo: Mu’assasa al-Halabi, 1968), iv, 669.