Shaykh Ṣālih Al-Fawzān (hafidahullāh):

From the Way of Allāh – The Glorified, The Most High – with his creation, is that he trials and tests them. He does not leave them without trials and tribulation, for if he was to leave mankind without trialling them, then the believer would not be distinguished from the hypocrite and the truthful would not become clear from the liar.

Source: Official Website of the Shaykh