Translation:

51. And remember We appointed forty nights for Moses and in his absence you took the calf (for worship) and ye did grievous wrong.

Notes (Tafseer)

66. This was after the Ten Commandments and the Laws and Ordinances had been given on Mount Sinai: Moses was asked up into the Mount, and he was there forty days and forty nights: Exod. xxiv. 18. But the people got impatient of the delay, made a calf of melted gold, and offered worship ande sacrifice to it: Exod. xxxii 1-8.