Quran 41.51-53
When We show favour unto man, he withdraweth and turneth aside, but when ill toucheth him then he aboundeth in prayer. Bethink you: If it is from Allah and ye reject it - Who is further astray than one who is at open feud (with Allah)? We shall show them Our portents on the horizons and within themselves until it will be manifest unto them that it is the Truth. Doth not thy Lord suffice, since He is Witness over all things?