‘Umar b. al-Khattab and Abu Huraira reported God’s messenger as saying that if anyone says, on seeing someone who is suffering affliction, “Praise be to God who has kept me free from the affliction He has brought on him and has shown me favour above many whom He has created,” that affliction, whatever it may be, will not smite him.
Tirmidhi transmitted it, and Ibn Majah transmitted it from Ibn ‘Umar. Tirmidhi said this is a gharib tradition, and ‘Amr b. Dinar, the transmitter, is not strong.