He would say any one of the following supplications: -

1. 
   
   O Allaah! Separate me (far) from my sins as you have separated (far) the East and West. O Allaah! Cleanse me of my sins as white cloth is cleansed from dirt. O Allaah! Wash me of my sins with water, ice and snow.
   He used to say this in obligatory prayers.⁹⁹
   
   
   
2. 
   
   I have set my face towards the Originator of the heavens and the earth sincerely [in Islam] and I am not among the Mushrikeen. Indeed my prayer, my sacrifice, my living and my dying are for Allaah, the Lord of the Worlds: no partner has He. With this I have been commanded, and I am the first of the Muslims (those who submit to Him).¹⁰⁰ O Allaah! You are the King, none has the right to br worshipped but You, [You are the Most Perfect & all Praise is for You] You are my Lord and I am Your slave¹⁰¹. I have wronged myself, and have acknowledged my sins, so forgive all my sins, for no-one forgives sins except You. Guide me to the best of characters, to which no- one can guide except You, and save me from the worst of characters, from which no-one can save except You. I am here and happy to serve you¹⁰². All good is in your Hands, and evil is not from You.¹⁰³ [The guided one is he who is guided by you.] I exist by your will and belong to You. [There is no escape or shelter from You except to You.] You are blessed and exalted. I seek Your forgiveness and repent to You.
   He used to say this in obligatory and voluntary prayers¹⁰⁴.
   
   
3. Similar to the above, without
   
   
   You are my Lord and I am Your slave to the end, with the following addition:
   
   
   O Allaah! You are the King, there is no (true) deity except You, glorified be You and praised.¹⁰⁵
   
   
   
4. Similar to no. 2 until
   
   
   and I am the first of the Muslims, adding:
   
   
   O Allaah, guide me to the best of characters and the best of actions, no one to which can guide except You, and save me from the evil characters and actions, from which no one except You can save (others) except You¹⁰⁶.
   
   
5. 
   
   You are Glorified¹⁰⁷, O Allaah, and Praised¹⁰⁸; Your Name is Blessed¹⁰⁹; Your Majesty¹¹⁰ is Exalted, and none has the right to worshipped but You.¹¹¹ He (sallallaahu 'alaihi wa sallam) also said, Indeed, the words most loved by Allaah are when His slave says: You are glorified, O Allaah¹¹²
   
   
   
6. Similar to the above, adding in prayer at night:
   
   
   There is no true god except Allaah, three times, and
   
   
   Allaah is the Greatest, Very Great, three times.
   
7. 
   
   Allaah is the Greatest, very great. Praise be to Allaah, again and again. Glorified is Allaah morning and evening - one of the Companions commenced with this, to which the Messenger (sallallaahu 'alaihi wa sallam) said: Wonderful for it (the supplication) is that the doors of the heavens were opened for it.¹¹³
   
   
   
8. 
   
   Praise be to Allaah, many, pure, blessed praises. Another man commenced with this, to which he (sallallaahu 'alaihi wa sallam) said: I saw twelve angels competing as to which of them would take it up.¹¹⁴
   
   
   
9. 
   
   
   O Allaah, to You belongs all Praise. You are the Light¹¹⁵ of the heavens and the earth and all those in them; to You belongs all Praise. You are the Maintainer¹¹⁶ of the heavens and the earth and all those in them; [to You belongs all Praise. You are the King of the heavens and the earth and all those in them] to You belongs all Praise. You are the Haqq¹¹⁷; Your promise is haqq; Your saying is haqq; meeting You is haqq; Paradise is haqq; the Fire is haqq; the Hour is haqq; the Prophets are haqq; Muhammad is haqq. O Allaah! to You I have submitted; in You I have placed my trust; in You I have believed; to You I have turned; for Your sake I have fought; to You I have referred for judgement; [You are our Lord and to You is the end of all journeys: so forgive me my earlier and later sins, what I have concealed and what I have showed] [and whatever else You know about more than I.] You are the Bringer- Forward and You are the Delayer; [You are my deity;] and none has the right to worshipped but You.¹¹⁸ [and there is no might nor power except with You].
   
   He (sallallaahu 'alaihi wa sallam) used to say this in prayer at night, as he did the following supplications:¹¹⁹
   
   
   
10. 
    
    O Allaah, Lord of Jibraa'eel, Meekaa'eel and Israafeel, Creator of the heavens and the earth, Knower of all that is hidden and open! It is You that will judge between Your servants in those matters about which they used to differ. Guide me by Your Grace to the Truth concerning that about which they differed, for indeed You guide whomsoever You wish to a path that is straight.¹²⁰
    
    
    
11. He would say takbeer, tahmeed, tasbeeh, tahleel and istighfaar ten times each, and then say,
    
    
    O Allaah! forgive me and guide me and give me sustenance and [overlook my sins] ten times, and then say:
    
    
    O Allaah! I seek refuge with You from the distress of the Day of Account ten times.¹²¹
    
    
    
12. 
    
    "Allaah is the Greatest [three times], Possessor of Kingdom, Power, Magnificence and Might."¹²²