اللَّهُمَّ آتِ نَفْسِي تَقْوَاهَا وَزَكِّهَا أَنْتَ خَيْرُ مَنْ زَكَّاهَا أَنْتَ وَلِيُّهَا وَ مَوْلَاهَا
Allāhumma Āti Nafsī Taqwāhā wa Zakkihā Anta Khayru man Zakkāhā Anta Waliyyuhā wa Mawlāhā
O Allah, grant my soul its piety and purify it, You are the Best to purify it, You are its Guardian and Master.
The Prophet sal Allahu alayhi wa sallam narrated this duaa in a Hasan (good) hadeeth in Tirmidhi and Ahmad:
اللَّهُمَّ إِنِّي أَسْأَلُكَ حُبَّكَ وَحُبَّ مَنْ يُحِبُّكَ وَحُبَّ عَمَلٍ يُقَرِّبُنِي إِلَى حُبِّكَ
Allāhumma Innī As’aluka Ḥubbaka Wa Ḥubba Man Yuḥibbuka Wa Ḥubba cAmalin Yuqarribunī Ilā Ḥubbika
O Allah, I ask You for Your Love, and the love of whoever loves You, and the love of deeds that will bring me closer to Your Love.
In Saheeh Muslim it is related that Abdullah ibn Mas’ood radi Allahu anhu narrated that the Prophet sal Allahu alayhi wa sallam used to supplicate,
اللَّهُمَّ إِنِّي أَسْأَلُكَ الهُدَى وَ التُّقَى وَ العَفَافَ وَ الغِنَى
Allāhumma Innī As’aluka al-Hudā Wat-Tuqā Wal-cAfāfa Wal-Ghinā
“O Allah, I ask You for guidance, piety, abstinence (from the unlawful) and modesty, and contentment and sufficiency.”
The Prophet sal Allahu alayhi wa sallam narrated this duaa in a hadeeth in Sunan an-Nisaa’i (authenticated by Shaykh Albaani):
اللَّهُمَّ إِنِّي أَسْأَلُكَ لَذَّةَ النَّظَرِ إِلَى وَجْهِكَ وَالشَّوْقَ إِلَى لِقَائِكَ
Allahumma Innī As’aluka Ladhdhata an-Naẓari ilā Wajhika wash Shawqa ilā Liqā’ik
O Allah, I ask You for the delight of gazing at Your Countenance and the eagerness of meeting You.
In a Saheeh (authentic) hadeeth in Sunan Ibn Maajah, A’ishah radi Allahu anha narrated that the Prophet sal Allahu alayhi wa sallam taught her this duaa:
اللَّهُمَّ إِنِّي أَسْأَلُكَ الْجَنَّةَ وَمَا قَرَّبَ إِلَيْهَا مِنْ قَوْلٍ أَوْ عَمَلٍ وَأَعُوذُ بِكَ مِنْ النَّارِ وَمَا قَرَّبَ إِلَيْهَا مِنْ قَوْلٍ
أَوْعَمَلٍ وَأَسْأَلُكَ أَنْ تَجْعَلَ كُلَّ قَضَاءٍ قَضَيْتَهُ لِي خَيْرًا
Allāhumma Innī As’alukal-Jannaħ Wa Mā Qarraba Ilayhā Min Qawlin Aw cAmalin Wa Acūdhu Bika Min-Nāri Wa Mā Qarraba Ilayhā Min Qawlin Aw cAmalin Wa As’aluka An Tajcala Kulla Qaḍā’in Qaḍaytahu Lī Khayran
O Allah, I ask You of Paradise and every deed or speech that will be a means of drawing near to it; and I seek refuge in You from the Fire and from every deed or speech that will be a means of drawing near to it; and I ask You that You make whatever You have decreed for me a means of good.
http://www.tayyibaat.com/2009/09/14/ramadan-duaa-series-success-in-the-hereafter/
