In one of his final messages to Bnai Yisrael in Parshat Nitzavim, Moshe prophesized that after he passed away Bnai Yisrael would turn away from Hashem. They would suffer, go into exile, and feel like Hashem abandoned them.
There have been many times throughout history when it appeared as if Hashem has abandoned us. Many tragic expulsions and massacres have taken the lives of many Jews, even of those Jews who felt secure in their societies. Jews contributed to the economies of Spain and Germany, yet they were still persecuted. The fact that they felt secure showed that they had been willing to adopt the gentile way of life.
Assimilation has always been a greater threat to the Jewish nation than oppression has been. Many Jews retained their faith in the ghettos, but today many have abandoned their religion for the “good life.” Persecutions have always served as tragic reminders that a Jew is considered a Jew wherever he is, even if he no longer considers himself one.
Despite these oppressions, Hashem has never been completely hidden. Had He left us, the Jewish People would have ceased to exist a long time ago. Hashem is still is our Guardian, even though His presence may not be obvious. An obvious example of this point is the Purim story. Even though no supernatural events occurred to save the Jews, the events that took place could only have been engineered by Hashem.
We should hope for the day when Hashem will once again appear openly to us. In order for this to happen, we must perform good deeds, never forget that Hashem is the only God, and never wander from His ways.