Allah does not change the condition of a people until they change what is in themselves

Q: What is the interpretation of the saying of the Exalted, Blessed and Exalted is He, in Surat al-Ra'd: [al-Ra'd: 11]?
A: This noble verse is a great verse indicating that Allah, Blessed and Exalted is He, in His perfect justice and perfect wisdom, does not change the condition of a people from good to evil, from evil to good, from prosperity to hardship, or from hardship to prosperity, until they change what is in themselves. If they are in righteousness and uprightness, and they change [their state], Allah changes their condition by means of punishments, calamities, hardships, drought, famine, division, and other types of punishments as a just recompense. He, the Exalted, said: [Fussilat: 46].
He, the Exalted, may also delay them, grant them respite, and lead them on, hoping that they will return, and then they are taken by surprise, as He, the Exalted, said: [al-An'am: 44], meaning they are despairing of all good. We seek refuge in Allah from the punishment and wrath of Allah. They may also be postponed until the Day of Resurrection, in which case their punishment will be more severe, as He, the Exalted, said: [Ibrahim: 42]. The meaning is that they are postponed and granted respite until after death, and that will be greater in punishment and more severe in wrath.
They may also be in evil, affliction, and sin, and then they repent to Allah, return to Him, feel remorse, and become upright in obedience; so Allah changes what is in them of misery and division, and of hardship and poverty, to prosperity, blessing, unity of word, and improvement of their condition, by means of their good deeds and their repentance to Allah (peace and blessings be upon him). And it has come in another verse: [al-Anfal: 53]. This verse clarifies to us that if they are in blessing, prosperity, and good, and then they change [their state] through sins, He changes their condition—there is no power nor strength except with Allah—and they may be granted respite as mentioned before. The reverse is also the case: if they are in badness and sins, or disbelief and misguidance, and then they repent, feel remorse, and become upright in the obedience of Allah, Allah changes their condition from the bad state to the good state. He changes their division to unity and harmony, changes their hardship to blessing, health, and prosperity, and changes their condition of drought, famine, scarcity of water, and the like, to the sending down of rain, the growth of the earth, and other types of good.