Why does the Holy Qur’an describe the reward of believers in different ways?

Because the description follows the context in which it stands. Each passage highlights the aspect of the reward that fits what has just been said.

Anyone who reads the Holy Qur’an carefully will notice that the reward of the believers is not described in the same words everywhere. In one place it speaks of gardens and streams, in another of a reward without end. One might think that different people are meant. But that is not the reason.

What matters is the context. Each description responds to what has been said just before. The first verse above is a good example. Shortly before it, the Holy Qur’an warns that man, after a long development, can fall back to the very lowest level. That is a serious warning to all of humanity.

The description of the reward fits this exactly. The believers do not fall back. They keep moving forward, and their progress has no end. So the word for a never-ending reward is the answer to the danger of falling back. It describes the aspect of the reward that matters in that place.

It is the same everywhere. It is not the believers themselves who determine which word is used, but the text that comes before. All these descriptions show different sides of the same reward. And none of them captures it fully, for the Holy Qur’an itself says that no one knows what joy is kept hidden for the believers.