Why does one feel regret for doing good, especially when showing kindness to those who have wronged them, or helping those who may surpass them, despite their initial feeling of spiritual elevation and desire to apply the Hadith: "Love for your brother what you love for yourself"?

What a Muslim finds of regret over doing good is from the whispers of Satan, which aim to sadden the believer and prevent him from continuing to do good and earn reward. These thoughts must be resisted, and one should frequently contemplate the virtues of good deeds and be encouraged by them. It has been said: "Indeed, the generous person is bountiful in doing good, and perhaps he regrets it, while the miser refrains from doing good, and then he regrets it."