זוהר בראשית — דף רכ ע”ב

When a person is ill, Divine Judgment rules over him. Whoever visits the sick removes a portion of that Judgment from them. For this reason, the commandment of visiting the sick is equivalent to all other commandments. When Israel suffers in exile, the Holy One blessed be He visits them. Exile is like an illness that Israel passes through until the Redemption arrives.