And indeed, he has seen the great Signs of his Lord. (The shackles of mental and physical bondage will be broken and humanity will come from darkness to Light (7:157), (17:1), (20:23-24))
and he did indeed see some of his Lord’s greatest signs
Dr. Munir Munshey
He definitely saw one of the greatest signs of his Lord
Dr. Kamal Omar
Surely, indeed he witnessed some of the great Signs of his Nourisher-Sustainer. [Please note that two different incidents are recorded in these initial verses of the Surah. One thing which is common to both the incidents is the descent of angel-Jibriel. The ascent of the person who is receiving the Inspiration is mentioned nowhere. It appears that some life-generating Rays or Light was showered by Allah on a garden that appeared extinct. The Life-giving source revived the garden in original state to make the recipient of Inspiration witness some of the Great Signs out of the Miraculous Signs of Allah]