Is it true that the Prophet, peace and blessings be upon him, and his companions used to train solely for increasing endurance and not for bulking up? And is bodybuilding training absolutely forbidden?

The practice of bodybuilding is permissible if it is free from শরعية prohibitions. A person is praised or blamed for practicing it according to their intention and method of practice. The Companions did not practice this sport because it did not exist in their time. Citing the حديث: "The example of a believer is like a young tender plant, its leaves sway wherever the wind blows, but when the wind stops, it straightens up. Similarly, a believer is afflicted with trials. And the example of a disbeliever is like a sturdy cedar tree, standing firm until Allah breaks it when He wills," is incorrect, as the حديث provides an example of a believer being exposed to trials and distinguishing them from the wicked and the hypocrites.