B.G 2.29
āścaryavat paśyati kaścidenam āścaryavad vadati tathaiva cānyaḥ। āścaryavaccainamanyaḥ śar̥ṇoti śrutvāpyenaṁ veda na caiva kaścit ॥2-29॥
Some one sees him as a marvel, someone speaks of him as a marvel, others hear him as a marvel. Yet even after such a hearing, no one knows him at all.
Gīta Tātparya 2.29
Lord is a marvel, despite knowing him as a marvel, we forget his speciality!
kiṁ tarhi āścaryo bhagavānevetyāha - āścaryavaditi। āścaryameva santamenam āścaryavat paśyati na punaḥ anāścaryam। "gaganaṁ gaganākāraṁ sāgaraṁ sāgaropam" -ityādivat।
What is the marvel of the Lord? - is stated in 'āścaryavat' verse. He is the marvel, because though he is perceived as a marvel, he is not seen as one. Here the lord is compared to himself as a marvel, similar to ancient sayings - "The Sky is of the form of Sky, the Sea is of the form of Sea."
"āścaryo bhagavān viṣṇuḥ yasmānnaitādr̥śaṁ kvacit। tasmāt tadgocaraṁ jñānaṁ tadgocaravadeva tu" -iti brahmatarke।
"Lord Vishnu is the marvel because, like him, we can't see any other. Therefore, the knowledge that enables to see Him, only he can see." - states Brahmatarka
anāścaryavadapi asurādayaḥ paśyantīti kaściditi viśeṣaṇam ॥29॥
The Lord is not a marvel, so say the demoniacal. Seeing the Lord like any other is their speciality.