The Quran

وَالَّذينَ آمَنوا وَعَمِلُوا الصّالِحاتِ وَآمَنوا بِما نُزِّلَ عَلىٰ مُحَمَّدٍ وَهُوَ الحَقُّ مِن رَبِّهِم ۙ كَفَّرَ عَنهُم سَيِّئَاتِهِم وَأَصلَحَ بالَهُم

Ali Unal

While those who believe and do good, righteous deeds, who believe in what has been sent on Muhammad – and it is the truth from their Lord – He will blot out from them their evil deeds (which will otherwise prevent their achievement of their goals in both worlds), and set their hearts fully aright, and improve their conditions (both in this world and the next).¹

Sincere faith and doing good, righteous deeds as required by faith cause one to have a sound, sincere, and satisfied heart. God leads such a person to right decisions, proper thoughts, and good actions, which in turn cause that person to deepen in faith and sincerity. The virtuous circle that is formed in this way will lead the believers to attain their (Islamic) goals in the world and eternal happiness in the Hereafter.