Imam Ali, Amir al-mu'minin, peace be upon him, said:

Ref: Al-Islam.org

وقال على عليه السلام : طُوبَى لِمَنْ ذَكَرَ الْمَعَادَ، وَعَمِلَ لِلْحِسَابِ، وَقَنِعَ بِالْكَفَافِ، وَرَضِيَ عَنِ اللهِ

Blessed is the person who kept in mind the next life, acted so as to be able to render account, remained content with what sufficed him and remained pleased with Allah.

وقال على عليه السلام : أَوْلَى النَّاسِ بِالْعَفْوِ أَقْدَرُهُمْ عَلَى الْعُقُوبَةِ

The most capable of pardoning is he who is the most powerful to punish.

وقال على عليه السلام : السَّخَاءُ مَا كَانَ ابْتِدَاءً، فَأَمَّا مَا كَانَ عَنْ مَسْأَلَةِ فَحَيَاءٌ وَتَذَمُّمٌ.

Generosity is that which is by one’s own initiative, because giving on being asked is either out of self-respect or to avoid rebuke.

وقال علي عليه السلام : مَنْ حَذَّرَكَ كَمَنْ بَشَّرَكَ

Whoever warns you is like one who gives you good tidings.

وقال علي عليه السلام : أَهْلُ الدُّنْيَا كَرَكْبٍ يُسَارُ بِهِمْ وَهُمْ نِيَامٌ

The people of the world are like travellers who are being carried while they are asleep.

وقال عليه السلام : لاَ تَسْتَحِ مِنْ إِعْطَاءِ الْقَلِيلِ، فَإِنَّ الْحِرْمَانَ أَقَلُّ مِنْهُ

Do not feel ashamed for giving little because refusal is smaller than that.

 وقال عليه السلام : الْعَفَافُ زِينَةُ الْفَقْرِ، والشُّكْرُ زِينَةُ الغِنَى

Charity is the adornment of destitution while gratefulness (to Allah) is the adornment of riches.