Q: When I was a teenager I used to commit many sins, but I did not abandon the obligations of Islam such as Salah (Prayer). Now, I am repentant to Allah of all sins, but I do not feel the sweetness of Iman (belief) and live in worry and confusion. When I repeat the Shahadah (Testimony of Faith), I feel that it does not reach my heart. I am afraid that Allah has set a seal on my heart (i.e. closed from accepting Allah's Guidance). Please, guide me. May Allah reward you well!
A: We advise you to frequently thank Allah for having guided you to Tawbah (repentance to Allah), to do lots of good deeds, to expect good from your Lord, to fill your time with Dhikr (Remembrance of Allah), to recite the EverGlorious Qur'an with contemplation, to befriend the righteous and to stay away from bad company. You should be hopeful of receiving good and having a good outcome, and you will feel In sha'aAllah (if Allah wills) after doing so the sweetness of Iman, the delight in saying Shahadah, and the fruits of sincere Tawbah. Allah (Glorified and Exalted be He) says: verily, in the remembrance of Allâh do hearts find rest. and: And all of you beg Allâh to forgive you all, O believers, that you may be successful The Prophet (peace be upon him) said: "Islam wipes out all that has gone before it (previous misdeeds)." He (peace be upon him) also said: "The one who repents from sin is like one who has not sinned."
A Muslim who frequently makes Dhikr and sincere Tawbah will gain success, peace of mind and ease of conscience and all past misdeeds will be forgiven. May Allah hold you steadfast to guidance and grant you uprightness! He is the best One asked for help.