Imam Ali(as) describing an incident to Holy Prophet(saww) narrates:
Today I happened to pass by Ammar Yasir who was apprehended by a Jew, who had loaned him thirty Dirhams. Ammar complained to me: Dear brother of Allah’s Messenger! This Jew has apprehended me only to give pain to me and disgrace me and that too only because I befriend you, Ahlul Bayt (a.s.). Kindly use your rank and position and get me released. I intended to request that Jew to favor Ammar with kindness but Ammar (r.a.) spoke up: Dear brother of Allah’s Messenger! Your honor in my eyes and heart is much more than that you make recommendation to him, who would never reject your word, even if you ask him to give feast to the whole world. Please just request Almighty Allah to help me to return his money and protect me from seeking loans in future.
So I raised my hands to the sky and prayed: O Allah! Please fulfill Ammar’s need. Thereafter I said to him: Pick up any stone or brick in front of you from the ground and it will turn into gold by Allah for you. So he picked up a stone weighing a few kilograms. It became gold in his hands. Then he asked the Jew: How much do I owe you? He replied: Thirty dirhams. He was asked how much in gold coins? He replied: Three Dinars. Ammar (r.a.) prayed to Allah Almighty: O Lord! Kindly make this gold soft so that I may slice it off and give to this Jew. Allah softened the metal. He took off three Mithqals gold and gave it to that Jew. Then looking at the remaining gold, I said: O Allah: I have heard that You have said in Holy Quran:
كلا ان الانسان ليطغي ان رءاه استغني
Nay! man is most surely inordinate, because he sees himself free from want.
I don’t wish to be that much wealthy. Therefore, O Allah: for the sake of one, for whom You made this stone, gold, please return it to its original form. So it became a stone and Ammar (r.a.) threw it away and exclaimed: O dear-most brother of Allah’s Messenger! Your friendship in this world and Hereafter is enough for me.
Upon hearing this, the Prophet of Allah (s.a.w.s.) said: Ammar’s contentment made even the angels wonder. They described Allah’s glory. Allah’s mercy continues to rain on him from high heavens. Then turning towards Ammar ibn Yasir (r.a.) he said: O Abal Yaqdhan: Good news for you. You, in honesty, are Ali’s (a.s.) brother and are the most high ranking in his friendship. You are among those who will be killed due to your devotion for him. You will be killed by a rebellious group and in this world, your last provision will be some uncooked milk and your soul shall join with the souls of Muhammad and his progeny (a.s.). You are, in my sight, among the desired Shias.
Source: Tafseer of Imam Hasan Askari(as), Sura Baqara, Verse 3