Kitāb al-Muʾmin
Hadith 3939 - وعن أبي جعفر (ع) قال إنّ الله (جلّ جلاله) إذا أحَبَّ عبداً غثَّه بالبلاء غثّاً وثَجّهُ بالبلاء ثَجّاً، فإذا دعاه قال: لبَّيكَ عبدي، لبّيك عبدي، لئِن عجّلتُ لك ما سألتَ إني على ذلك لقادرٌ، ولئِن ذخَرتُ لك فما أدَّخَرتُ لك خيرٌ لك.
39. It has been narrated that Abu Ja'far (a.s) said: When Allah loves a person, He chokes him with afflictions until he is immersed in them completely and trials flow towards him copiously. Then when he calls out to Him, He (Allah) replies, 'I am here My servant, here I am! If I wished to hasten towards you what you are asking for, then indeed I am able to do it; but what I have amassed for you (for the hereafter) is better for you.'