Abu Dharr reported: The Messenger of Allah, peace and blessings be upon him, said, “O Abu Dharr, do you say an abundance of possessions is wealth?” I said yes. The Prophet said, “Do you say a lack of possessions is poverty?” I said yes. The Prophet repeated this three times, then he said, “Wealth is in the heart and poverty is in the heart. Whoever is wealthy in his heart will not be harmed no matter what happens in the world. Whoever is impoverished in his heart will not be satisfied no matter how much he has in the world. Verily, he will only be harmed by the greed of his own soul.”

Source: Tibrani..

Grade: Sahih (authentic) according to Sh. Al-Albani

عن أبي ذر قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَا أَبَا ذَرٍّ تَقُولُ كَثْرَةُ الْمَالِ الْغِنَى قُلْتُ نَعَمْ قَالَ تَقُولُ قِلَّةُ الْمَالِ الْفَقْرُ قُلْتُ نَعَمْ قَالَ ذَلِكَ ثَلاثًا ثُمَّ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ الْغِنَى فِي الْقَلْبِ وَالْفَقْرُ فِي الْقَلْبِ مَنْ كَانَ الْغِنَى فِي قَلْبِهِ لا يَضُرُّهُ مَا لَقِيَ مِنَ الدُّنْيَا وَمَنْ كَانَ الْفَقْرُ فِي قَلْبِهِ فَلا يُغْنِيهِ مَا أَكْثَرَ لَهُ فِي الدُّنْيَا وَإِنَّمَا يَضُرُّ نَفْسَهُ شُحُّها