In the Holy Qur’an, Allah has stated One of His law, in regards to prophets. Allah States:
“Has not the time arrived for those who believe that their hearts should feel humbled at the remembrance of Allah and at the truth which has come down to them, and that they should not become like those who were given the Book before them and the term was prolonged for them, but their hearts were hardened, and many of them are wicked? Know that Allah is now quickening the earth after its death. We have made the Signs manifest to you, that you may understand” (Chapter 57 Verses 17-18)
Allah Has made it clear that after a long duration of time since the arrival of a prophet, the people become hard hearted and many become wicked. They become misguided and start to follow teachings which their prophet had never taught. After this occurs, Allah sends a prophet to revive the message and bring them back to the true teachings. This has allegorically been mentioned here and has been related to the earth and its dryness. The earth becomes dry and hard after it is deprived of rain for a long period and can only be cured by rain.
Hazrat Mirza Bashiruddin Mahmood Ahmad(ra) states:
“The verse seems to refer to the Latter-Day Muslims when as a result of neglecting the teachings of Islam they will have become spiritually corrupt, morally depraved and politically impotent. The verse means to bring home to them the realization of their all-round degradation and makes to them a pathetic appeal. “Has not the time arrived yet.” it seems to say to them, “Now that they have sunk to the lowest depths of degradation, they should turn to God and act upon the teachings of their religion which once raised them to the highest peaks of greatness, grandeur and glory”
He(ra) further states:
“In the preceding verse, Muslims were told that a time would come when, as the result of ignoring and neglecting the teachings of their religion, their hearts would turn away from God and incur His displeasure and consequently would become degraded and disgraced. But God would not leave them in the lurch. In conformity with His time honored-law, viz., that when the earth becomes dry, He sends down rain from Heavens and gives a new life to it. He will raise among them a great Divine Reformer and through him will bring about the renaissance of Islam, and Muslims will again see better days”(Five Volume Commentary of the Holy Qur’an, page 2582)