आश्चर्यवत्पश्यति कश्चिदेनम्' इति भगवद्वचनाच्च ।स्वरूपशक्तिव्यापारकार्यैः अद्भुतत्वा अद्भुतः ॥
In plain words
The Lord Himself said it: "Now and then someone sees this Self, and sees it as a wonder." And a wonder it is on every count — in what He is, in what He can do, in what He does, and in what comes of it. That is why He is called Adbhutaḥ, the Astonishing One.
Close to the Sanskrit
And from the statement of the Blessed One, 'Someone sees this one as a wonder' — being wondrous by His essential nature, His power, His activity and His effects, He is Adbhutaḥ, the Wondrous.