Reb Mendel of Kotzk once asked the following question:[1]
Why is it that the sin of the Golden Calf was forgiven although the Torah does not express that Israel repented, yet they were forgiven; however, the concerning the sin of the spies they repented but weren’t forgiven?
He answered:
When Israel sinned with the Golden Calf, they were searching for spirituality, stating “make for us a Lord,” and was therefore not as bad. However, the sin of the spies revolved around coarse gluttony.
[1] Emet Mkotzk Titzmach, Pg. 48
