If you commit a sin then do this and know this concerning your state:
Ahmad (26998) narrated that Abu’l-Darda’ (may Allaah be pleased with him) said: I heard the Messenger of Allaah (peace and blessings of Allaah be upon him) say: “The one who does wudoo’ and does it well, then stands and prays two rak’ahs or four (one of the narrators was uncertain), in which he remembers Allaah and focuses well, then asks Allaah for forgiveness, He will forgive him.”
The editor of al-Musnad said: its isnaad is hasan. It was also quoted by al-Albaani in Silsilat al-Ahaadeeth al-Saheehah (3398).
The Messenger of Allah (peace and blessings of Allaah be upon him) said:
“Allah will accept the repentance of His slave so long as the death rattle has not yet begun.” Classed as hasan by al-Albaani in Saheeh al-Tirmidhi (3537)
Sahih Muslim (2999) narrated that Suhayb (may Allaah be pleased with him) said: The Messenger of Allah (peace and blessings of Allaah be upon him) said:
“Strange are the ways of a believer for there is good in every affair of his and this is not the case with anyone else except in the case of a believer for if he has an occasion to feel delight, he thanks (God), thus there is a good for him in it, and if he gets into trouble and shows resignation (and endures it patiently), there is a good for him in it.”
Sahih Muslim (2664):
"A strong believer is better and is more lovable to Allah than a weak believer, and there is good in everyone, (but) cherish that which gives you benefit (in the Hereafter) and seek help from Allah and do not lose heart, and if anything (in the form of trouble) comes to you, don't say: "If I had not done that, it would not have happened so and so", but say: "Allah did that what He had ordained to do" (قَدَرُ اللَّهِ وَمَا شَاءَ فَعَلَ - Qadarul-lah wa ma sha'a fa'al) and your "if" opens the (gate) for the Satan."
Allah says in Surah al-Baqarah [155-157]:
"And We will surely test you with something of fear and hunger and a loss of wealth and lives and fruits, but give good tidings to the patient,
Who, when disaster strikes them, say, "Indeed we belong to Allah, and indeed to Him we will return."
Those are the ones upon whom are blessings from their Lord and mercy. And it is those who are the [rightly] guided."
Sahih Muslim (918): "If any Muslim who suffers some calamity says, what Allah has commanded him, "We belong to Allah and to Him shall we return; O Allah, reward me for my affliction and give me something better than it in exchange for it," (Inna lillahi wa inna ilayhi raji'un - Allahum-majurni fi musibati wa achlif-li khayran minha) Allah will give him something better than it in exchange."
Regarding the feeling that you assume you have a void heart, Allah says:
“Those who believe (in the Oneness of Allah - Islamic Monotheism), and whose hearts find rest in the remembrance of Allah, Verily, in the remembrance of Allah do hearts find rest”
“Is he whose heart Allah has opened to Islam, so that he is in light from His Lord (as he who is non-Muslim)? So, woe to those whose hearts are hardened against remembrance of Allah! They are in plain error!”
Therefore, your current state may indicate that you may have been neglectful with your life in terms of not praying, not doing your Dhikr (which you conduct after every obligatory prayer, at the specific time in the morning and evening, etc. - get the book Hisnul Muslim, which is a book that provides many Adhkar and Du'a for most circumstances), not abstaining from haram.
If you feel sorry for what you have done, then repent and seek forgiveness from Allah and intend that you will never go back to that kind of action. Make sure to pray 5 times a day and be focused in it and steadfast (get the book "The Prophet's Prayer Described" by Sheikh Albani), and to recite the Dhikr, and to not overexeggerate with worship, but to do as much as you can and live a halal life. Then, you will inshallah be successful and you will have a vital, fortunate, virtues and satisfying life.
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