Tafsir: At-Takathur 102:6

Verse [ 102:7] ثُمَّ لَتَرَ‌وُنَّهَا عَيْنَ الْيَقِينِ (...then you will see it with an eye of certainty.) The phrase 'ain-ul-yagin' (translated above as 'eye of certainty' ) refers to the certainty attained by physical observation, and this is the highest degree of certainty. Sayyidna Ibn ` Abbas ؓ reports that when Holy Prophet Musa (علیہ السلام) was on the mount of Tur, his people started worshipping a calf. Allah informed him about this while he was still on the mountain. This piece of information did not affect Musa (علیہ السلام) so much. However, when he returned and saw the Children of Israel, with his own eyes, worshipping the calf, he became so indignant that the tablets of Torah involuntarily fell from his hands. [ Transmitted by Ahmad and Tabarani with an authentic chain of narrators, as quoted by Mazhari ].