He who gives in charity the value of a date which was lawfully earned, and Allah only accepts that which has been lawfully earned, then Allah will accept it with His right hand and nurture it for him, just as one of you nurtures his foal, until it becomes like a mountain
Authentic hadithعن أبي هريرة رضي الله عنه مرفوعاً: «من تصدق بعدل تمرة من كسب طيب، ولا يقبل الله إلا الطيب، فإن الله يقبلها بيمينه، ثم يُرَبِّيها لصاحبها كما يُرَبِّي أحدكم فَلُوَّه حتى تكون مثل الجبل»
Abu Hurayrah (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: "He who gives in charity the value of a date which was lawfully earned, and Allah only accepts that which has been lawfully earned, then Allah will accept it with His right hand and nurture it for him, just as one of you nurtures his foal, until it becomes like a mountain."
Explanation
He who gives in charity the value of a date that was not earned through cheating and deceit, and Allah only accepts lawfully earned charity, so, Allah will accept it with His right hand – which we understand according to its apparent meaning, as befits Allah’s majesty, without interpreting or distorting the meaning of this attribute. The meaning of "Allah accepting it" is explained in a different narration in Sahīh Muslim, as it says that Allah will take it from him. He will then nurture it and multiply its reward, just as one of you raises his foal, which is a baby horse, until it grows and becomes an adult horse.
Source · Narrated by Bukhari & Muslim
From the Hadith Encyclopedia (hadeethenc.com).