It is not essential to do ghusl or wudoo’ in order for repentance to be valid
There is no human being who does not commit sin, and the best of them are those who hasten to repent. It was narrated from Anas that the Prophet (peace and blessings of Allaah be upon him) said: “Every son of Adam commits sin and the best of those who commit sin are those who repent.” Narrated by al-Tirmidhi, 2499; Ibn Maajah, 4251; classed as hasan by al-Albaani in Saheeh al-Jaami’, 3428.
Allaah has enjoined repentance upon His slaves, as He says (interpretation of the meaning):
“O you who believe! Turn to Allaah with sincere repentance! It may be that your Lord will expiate from you your sins, and admit you into Gardens under which rivers flow (Paradise)”
And Allaah has told us that He accepts the repentance of His slaves and forgives them; indeed He turns their bad deeds into good deeds. Allaah says (interpretation of the meaning):
“And He it is Who accepts repentance from His slaves, and forgives sins, and He knows what you do”
“Except those who repent and believe (in Islamic Monotheism), and do righteous deeds; for those, Allaah will change their sins into good deeds, and Allaah is Oft‑Forgiving, Most Merciful”
Allaah has not commanded the person who repents to do wudoo’ or ghusl, whether his impurity is minor or major, either before or after repenting, unless he is repenting from kufr (disbelief) or riddah (apostasy).
The scholars of the Standing Committee said:
Ghusl is not required after sincere repentance from sin, because the basic principle is that it is not prescribed, and we do not know of any evidence that differs from this principle except if the person is repenting from kufr, because it is prescribed for the one who enters Islam to do ghusl, because the Prophet (peace and blessings of Allaah be upon him) commanded Qays ibn ‘Aasim to do that when he became Muslim. Narrated by Imam Ahmad, Abu Dawood, al-Tirmidhi and al-Nasaa’i; classed as saheeh by Ibn al-Sakan.
Fataawa al-Lajnah al-Daa’imah, 5/317
The conditions of repentance according to the scholars are well known; they do not include wudoo’ or ghusl. These conditions are as follows:
1-Sincerity in repentance.
2-Giving up the sin.
3-Regretting the sin.
4-Resolving not to go back to the sin.
5-Repenting at the time when repentance is accepted, for Allaah does not accept repentance once the death rattle reaches the throat when the soul is being taken, or after the sun rises from the west.
6-Restoring rights to people if the sin had to do with transgressions against the rights of other people.
And Allaah knows best.