I have said very bad word to Allah out of anger and frustration due to bad behavior of my wife, Please suggest how can I ask for Allah's forgiveness.

Allah is Most Gracious and Most Merciful. He says in the Noble Qur'aan, 'Oh My Slaves! Do not despair. Verily Allah will forgive all sins.'%0D%0A%0D%0AIn one Hadith, Rasulullah (Sallallaahu Alayhi Wasallam) is reported to have said, 'If a person has sins equivalent to the foams of the sea and pebbles on a desert, Allah's mercy is so encompassing that He will forgive every sin.' In another narration, it is mentioned that Allah will speak secretly to one of His slaves on the day of Qiyaamat and remind him of all his sins. After the person will confess his sins, Allah will say to him, 'I concealed your faults in the world, today too, I will conceal your faults. Go in Jannah, I have forgiven you.'%0D%0A%0D%0AThe above mentioned are few of many Ahaadith explaining the extent of Allah's Mercy. However, Allah says, 'Verily Allah will not forgive a person who ascribe partners (commit Shirk) with Him.' The only sin that is unforgivable is Kufr (disbelief) and Shirk (ascribing partners). Accepting Islam is the only atonement for the sin of Kufr and Shirk. %0D%0A%0D%0AIf one fulfils the conditions of repentance, i.e. regret and make firm intention to reform, then surely Allah Ta'ala is Tawwaab (Most Forgiving) %0D%0A%0D%0Aand Allah Ta'ala Knows Best%0D%0A%0D%0AMufti Ebrahim Desai