Tribulation and calamity
Prophet Jacob (Pbuh) suffered from the absence of Joseph (Pbuh) for 20, or according to a narration, 40 years! Undoubtedly, God does not want to bother a believer, but rather intends to make him sincere through the affliction, so that his heart is focused only on God; affliction is the best ladder of Solƫk (spiritual growth and self-purification).