Ibn al-Qayyim -May Allah have mercy on him- said:

“And supplication is from the most beneficial cures. and it is the enemy of a calamity, it repels it (the calamity), it cures it, and it prevents it from descending and it removes it or lessen it when it descends and it is the weapon of the believer.”

[Al-jawāb Al-kāfī Liman Sa’ala An Ad-dawā’ Ash-Shāfī 1/10]