‘Uthmān ibn ‘Affān (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: "He who performs ablution perfectly, his sins will leave his body, even coming out from under his nails.”
شرح الحديث :
This Hadīth indicates that ablution is one of the best acts of worship. One of the virtues of ablution mentioned in this Hadīth is that when a person performs it perfectly, by observing its Sunnahs and manners, this will expiate his minor sins, pertaining to Allah's rights, to the extent that sins will come out from under his nails. Therefore, one should intend by his ablution to draw closer to Allah, Exalted and Glorified. One should keep in mind that by making ablution he is complying with Allah's commandment mentioned in the verse: ﴿When you rise to [perform] prayer, wash your faces﴾ [Sūrat al-Mā'idah: 6]. In addition, he should keep in mind that he is following the way of the Messenger of Allah (may Allah's peace and blessings be upon him) in his ablution, and that he is seeking the reward of Allah, and that he will be rewarded for this, the thing that will drive him to perfect his ablution.