Abu Dharr (radi Allahu anhu) said: “While I was walking with the Prophet in the Harra of Medina, Uhud came in sight. The Prophet said, ‘O Abu Dharr!’ I said, ‘Labbaik, O Allah’s Apostle!’ He said, ‘I would not like to have gold equal to this mountain of Uhud, unless nothing of it, not even a single Dinar of it remains with me for more than three days, except something which I would keep for repaying debts. I would have spent all of it (distributed it) amongst Allah’s Slaves like this, and like this, and like this.’ The Prophet pointed out with his hand towards his right, his left and his back (while illustrating it). He proceeded with his walk and said, ‘The rich are in fact the poor (little rewarded) on the Day of Resurrection except those who spend their wealth like this, and like this, and like this, to their right, left and back, but such people are few in number.’” [Sahih Bukhari]
This hadith tells us that wealth is only beneficial when it is spent in Allah’s Path and among His slaves for His pleasure. Otherwise it is harmful, for it will be inquired about on the Day of Judgement.
Al-Ahnaf bin Qais (radi Allahu anhu) narrated that once while he was sitting with some people from Quraish, a man with very rough hair, clothes, and appearance came and stood in front of them, greeted them and said, “Inform those who hoard wealth, that a stone will be heated in the Hell-fire and will be put on the nipples of their breasts till it comes out from the bones of their shoulders and then put on the bones of their shoulders till it comes out through the nipples of their breasts, the stone will be moving and hitting.” After saying that, the person retreated and sat by the side of the pillar. Al-Ahnaf (radi Allahu anhu) followed him and sat beside him, as he did not know who the man was. So he said to him, “I think the people disliked what you said.” The man replied, “These people do not understand anything, although my friend told me so.” Al-Ahnaf bin Qais (radi Allahu anhu) asked, “Who is your friend?” The man replied, “The Prophet said (to me), ‘O Abu Dharr! Do you see the mountain of Uhud?’ And on that I (Abu Dhar) started looking towards the sun to judge how much remained of the day as I thought that Allah’s Apostle wanted to send me to do something for him and I said, ‘Yes!’ He said, ‘I do not love to have gold equal to the mountain of Uhud unless I spend it all (in Allah’s cause) except three Dinars (pounds).’ These people do not understand and collect worldly wealth. No, by Allah, neither do I ask them for worldly benefits nor am I in need of their religious advice till I meet Allah, the Honorable, the Majestic.’” [Sahih Bukhari]
Soon after the Prophet’s death many Muslims forgot about the advice of the Prophet (sal allahu alaihi wa sallam) in which he warned them against chasing and accumulating the things of this world. Abu Dharr (radi Allahu anhu) would keep reminding people of this, because of which he became very unpopular.
During the Khilafah of Uthman (radi Allahu anhu) Abu Dharr (radi Allahu anhu) was in Shaam for some time where Muawiya (radi Allahu anhu) was the governor. His preaching was not appreciated. In his own words: “I was in Sham and differed with Muawiya on the meaning of, ‘They who hoard up gold and silver and spend them not in the way of Allah.’ [Quran 9:34]. Muawiya said, ‘This verse is revealed regarding the people of the scriptures.’ I said, ‘It was revealed regarding us and also the people of the scriptures.’ So we had a quarrel and Muawiya sent a complaint against me to Uthman.”
“Uthman wrote to me to come to Medina, and I went to Medina. Many people came to me as if they had not seen me before. So I told this to Uthman.” For this reason Uthman (radi Allahu anhu) allowed him to leave Medina, which he did and he settled alone in a place called Ar-Rabadha. He did not leave Medina in disobedience of Uthman (radi Allahu anhu). [Sahih Bukhari]