Remembrance of Allah --Seeking Forgiveness

Seeking forgiveness is the cause for the forgiveness of sins, entry into paradise, warding off calamities, and the increase of wealth and children. Allah, glorified be He, says: 

فَقُلْتُ ٱسْتَغْفِرُوا۟ رَبَّكُمْ إِنَّهُۥ كَانَ غَفَّارًۭا ١٠

يُرْسِلِ ٱلسَّمَآءَ عَلَيْكُم مِّدْرَارًۭا ١١

وَيُمْدِدْكُم بِأَمْوَٰلٍۢ وَبَنِينَ وَيَجْعَل لَّكُمْ جَنَّـٰتٍۢ وَيَجْعَل لَّكُمْ أَنْهَـٰرًۭا ١٢

"So I said, 'Ask forgiveness of your Lord. Indeed, Indeed, He is ever a Perpetual Forgiver. He will send [rain from] the sky upon you in [continuing] showers and give you increase in wealth and children and provide for you gardens and provide for you rivers.'"  

(Surah Nuh : Ayat 10-12)

It is also a means for a happy life and abundant blessings. Allah, glorified be He, says:

وَأَنِ ٱسْتَغْفِرُوا۟ رَبَّكُمْ ثُمَّ تُوبُوٓا۟ إِلَيْهِ يُمَتِّعْكُم مَّتَـٰعًا حَسَنًا إِلَىٰٓ أَجَلٍۢ مُّسَمًّۭى وَيُؤْتِ كُلَّ ذِى فَضْلٍۢ فَضْلَهُۥ ۖ وَإِن تَوَلَّوْا۟ فَإِنِّىٓ أَخَافُ عَلَيْكُمْ عَذَابَ يَوْمٍۢ كَبِيرٍ ٣

“And [saying], "Seek forgiveness of your Lord and repent to Him, [and] He will let you enjoy a good provision for a specified term and give every doer of favor his favor. But if you turn away, then indeed, I fear for you the punishment of a great Day”. 

(Surah Hud: Ayat 3)

Through seeking forgiveness, one's strength is increased. Prophet Hud said to his people:

وَيَـٰقَوْمِ ٱسْتَغْفِرُوا۟ رَبَّكُمْ ثُمَّ تُوبُوٓا۟ إِلَيْهِ يُرْسِلِ ٱلسَّمَآءَ عَلَيْكُم مِّدْرَارًۭا وَيَزِدْكُمْ قُوَّةً إِلَىٰ قُوَّتِكُمْ وَلَا تَتَوَلَّوْا۟ مُجْرِمِينَ ٥٢

"And O my people, ask forgiveness of your Lord and then rHim, and He will send [rain from] the sky upon you in showers and increase you in strength [added] to your strength. And do not turn away, [being] criminals." 

(Surah Hud: Ayat 52)

Seeking forgiveness is also a means for the descent of mercy from the heavens. Allah, the Most High, says: 

قَالَ يَـٰقَوْمِ لِمَ تَسْتَعْجِلُونَ بِٱلسَّيِّئَةِ قَبْلَ ٱلْحَسَنَةِ ۖ لَوْلَا تَسْتَغْفِرُونَ ٱللَّهَ لَعَلَّكُمْ تُرْحَمُونَ ٤٦

"He said, 'O my people, why are you impatient for evil before [i.e., instead of] good? Why do you not seek forgiveness of Allah that you may receive mercy?'" (Surah An-Naml: Ayat  46)

Seeking forgiveness removes sins and the harm of disobedience. Qatadah1, may Allah have mercy on him, said: "Verily, this Quran guides you to your diseases and their remedies. As for your disease, it is sins, and as for your remedy, it is seeking forgiveness."2

The Prophet, peace be upon him, used to frequently seek forgiveness. He said,

There is (at times) some sort of shade upon my heart3, and I seek forgiveness from Allah a hundred times a day". 

Abu Al-Minhāl1, may Allah have mercy on him, said, "No neighbor is dearer to a person in his grave than seeking forgiveness."2

So, increase in seeking forgiveness at all times, and it will rectify your religious and worldly affairs.

(Muslim)4

References:

1 He is Abu Al-Khattab Qatadah ibn Da'amah ibn Qatadah Al-Sadusi. He was born in 60 AH and passed away in 118 AH. Sīyar Aʻlām al-Nubalā'" (269/5) and "Taqrīb al-Tahdhīb" (453/1).

2 Jamiʻ al-ʻUlūm wal-Ḥikam (415/2).

3 "Mashāriq al-Anwār ʻalá Ṣaḥāḥ al-Āthār" (142/2).

4 Book of Remembrance, Supplication, Repentance, and Seeking Forgiveness, chapter on the recommendation of seeking forgiveness and increasing it, number (2702), from the narrationepent to 

of Al-Agharr Al-Muzani, may Allah be pleased with him.

1 He is Abdur-Rahman ibn Mut'im Al-Banani Al-Basri Al-Makki. He passed away in 106 AH. "Taqrīb al-Tahdhīb" (p. 350).

2 Jamiʻ al-ʻUlūm wal-Ḥikam (415/2).