In Paradise, there is a tree under the shadow of which a rider can travel for a hundred years.
The Book of Paradise, its Description, its Bounties and its Inhabitants - Sahih Muslim 2826 a
This narration describes one of the magnificent trees in Paradise, known as the "Tūbā" tree or other blessed trees. The immense scale indicates Paradise's boundless expanse, where a rider on a fast horse would need a century to cross just the shadow of a single tree. This demonstrates Allah's infinite generosity and the unimaginable vastness of the Hereafter's rewards for believers.
Classical scholars like Ibn Kathir and al-Nawawi explain this illustrates Paradise's perfection where everything is magnified beyond worldly comprehension. The "hundred years" signifies an extremely long distance, emphasizing that Paradise's delights far exceed human imagination and worldly limitations.
This hadith serves to strengthen faith and encourage righteous deeds by giving believers a tangible, though unimaginable, image of the eternal rewards awaiting them in the Hereafter.