All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
You should know that speaking of Allaah, The Exalted, using the third or second person pronoun does not reflect any disrespect to Him; Exalted is He. We find the Quran talking about Allaah using the third person; for instance, Allaah says (what means): {He is Allaah, other than whom there is no deity, Knower of the unseen and the witnessed. He is the Entirely Merciful, the Especially Merciful.} [Quran 59:22] There are endless examples in the Quran in which Allaah is mentioned in the third person mode.
Moreover, Allaah is generally spoken of in the third person in the statements and supplications of the Prophet, sallallaahu ‘alayhi wa sallam, using singular pronouns. There is no doubt that the Prophet, sallallaahu ‘alayhi wa sallam, was the keenest on glorifying Allaah in the most perfect manner and that he, sallallaahu ‘alayhi wa sallam, knew the rights of Allaah the best.
It is also allowable to address Allaah using the plural pronouns. Allaah, The Exalted, says (what means): {...he says: My Lord, send me back.} [Quran 23:99] The Arabic imperative verb used in the verse Irji‘oon is the plural form of the singular verb Irji‘ which means to return. Scholars of Hadeeth underlined that the verb Irju‘oon was used in the verse in the plural form for the purpose of glorifying the addressee, i.e. Allaah, The Exalted.
In any case, this is not the best way of addressing Allaah, The Exalted. The best and most perfect manner to address Allaah, The Exalted, is that which is used in the statements of the Prophet, sallallaahu ‘alayhi wa sallam, speaking to Allaah and supplicating Him, and it was all using the singular pronouns. For example, the Prophet, sallallaahu ‘alayhi wa sallam, said, "Allaahumma ighfir lee warhamni... (O my Lord; bestow your forgiveness and mercy on me)." There are numerous similar examples in the Sunnah. Indeed, the best and most perfect guidance is the guidance of Prophet Muhammad, sallallaahu ‘alayhi wa sallam.
Allaah knows best.