All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
The Hadeeth reported on the authority of ‘Abdullah Ibn ‘Umar is narrated by Imams Ahmad, At-Tirmithi, An-Nasaa’i, Ibn Maajah, Abu Ya'la and others. The text of the Hadeeth in Sunan At-Tirmithi is as follows: The Prophet said: “If anyone drinks wine, Allah will not accept prayer from him for forty days, but if he repents Allah will forgive him. If he repeats the offence Allah will not accept prayer from him for forty days, but if he repents Allah will forgive him. If he again repeats the offence Allah will not accept prayer from him for forty days, but if he repents Allah will forgive him. If he repeats it a fourth time Allah will not accept prayer from him for forty days, and if he repents Allah will not forgive him, but will give him to drink of the river of the fluid flowing from the inhabitants of Hell.” Imam Al-Tirmithi graded it as Hassan, Al-Haakim graded it as Saheeh (authentic).
Ibn Hajar said in his book Al-Musaddad that Al-Munthiri accepted the ruling given by Al-Haakim. There is a similar Hadeeth to the above Hadeeth from Abu Thar in Musnad Imam Ahmad.”
The Prophet's saying: “If he repents Allah will not forgive him is only to give a severe warning and strong threat to prevent one from committing such a dreadful act; otherwise, Allah will accept his repentance as reported in a Hadeeth that the Prophet said: “He who asks pardon (seeking forgiveness) is not considered an insistent on a sin, even if he returns to his sin seventy times a day.” [Abu Daawood and At-Tirmithi]
As for the Hadeeth that reads that the one who drinks a forth time or a fifth time should be killed, it is an abrogated and fabricated one.
Imam An-Nawawi wrote in his explanation of Saheeh Muslim: “Muslim scholars are agreed that the Hadd (the corporal punishment prescribed by Islamic law) should be carried out against the one who drinks alcohol regardless of its quantity. They also agree that a person is not killed even if he repeatedly drinks it. This consensus is also reported by At-Tirmithi, Qaadhi ‘Iyadh and many other scholars. The exceptional opinion that approves killing the one who drinks a fifth time is not correct and contrary to the agreement of the companions and their followers.
Allah knows best.