Do you want your sustenance (rizq) to increase? Do you want to have children? Do you want to have affluence in your wealth and everything? Do you want more and more? Then make istighfar (Ask Allah's forgiveness) as much as you can:
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Allah the Almighty says:
"I said (to them): 'Ask forgiveness from your Lord; Verily, He is Oft-Forgiving * He will send rain to you in abundance * And give you increase in wealth and children, and bestow on you gardens and bestow on you rivers ”
Chapter of Nuh, 71:10-12.
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From the Sunna:
Here is the master of forgiveness:
The Messenger of Allâh, ﷺ , said:
"The master of invocations for forgiveness is that the servant says:
Arabic:
َعنْ شَدَّادُ بْنُ أَوْسٍ رَضِيَ اللَّهُ عَنْهُ عَنْ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ سَيِّدُ الِاسْتِغْفَارِ أَنْ تَقُولَ اللَّهُمَّ أَنْتَ رَبِّي لَا إِلَهَ إِلَّا أَنْتَ خَلَقْتَنِي وَأَنَا عَبْدُكَ وَأَنَا عَلَى عَهْدِكَ وَوَعْدِكَ مَا اسْتَطَعْتُ أَعُوذُ بِكَ مِنْ شَرِّ مَا صَنَعْتُ أَبُوءُ لَكَ بِنِعْمَتِكَ عَلَيَّ وَأَبُوءُ لَكَ بِذَنْبِي فَاغْفِرْ لِي فَإِنَّهُ لَا يَغْفِرُ الذُّنُوبَ إِلَّا أَنْتَ قَالَ وَمَنْ قَالَهَا مِنْ النَّهَارِ مُوقِنًا بِهَا فَمَاتَ مِنْ يَوْمِهِ قَبْلَ أَنْ يُمْسِيَ فَهُوَ مِنْ أَهْلِ الْجَنَّةِ وَمَنْ قَالَهَا مِنْ اللَّيْلِ وَهُوَ مُوقِنٌ بِهَا فَمَاتَ قَبْلَ أَنْ يُصْبِحَ فَهُوَ مِنْ أَهْلِ الْجَنَّةِ. رواه البخاري (6306)
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(Transliteration)
'Allâhumma 'anta rabbî, lâ 'ilâha 'illâ 'anta, khalaqtanî, wa 'anâ `abduka, wa 'anâ `alâ `ahdika wa wa`dika mastata`tu, 'a`outhu bika min sharri ma sana`tu, 'abû'u laka bini`matika 'alayya, wa 'abû'u bithambî, faghfirlî fa'innahu lâ yaghfiru 'aththunûba 'illâ 'anta.
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English translation:
O' my 'ilâh You are my Lord, there is no 'ilâh but You. You created me, and I am your bondservant, and I will stick to my covenant and promise [of faith and sincere obedience] to You, as to my ability. I seek refuge in You from the evil of what I have done, I acknowledge, to You, your bounties upon me, and I acknowledge, to You, my sin. Thus forgive me, for none forgives sins except You.Whoever says this as he enters upon evening, then, dies that night, he would enter Paradise; and if one says this as he enters upon morning, then, dies that day, he would enter Paradise".
Reported by Al-Bukhari.