Tawbah - He reviled Islam a great deal, and every time he wanted to repent the Shaytaan whispered to him that he was excusedbecause he was angry

I reviled Islam on many occasions, Allah forbid, but when I repent he
says to me: you were angry and you did not do that deliberately. Then
I doubt myself: wasI angry or not? was it deliberate or not? What
should I do?.
Praise be to Allaah.
Reviling Islam is kufr andapostasy from Islam, according to scholarly
consensus. The one who does that has to repent to Allah sincerely, by
regretting what he has done and resolving not to go back to it. If he
repents, Allah will accepthis repentance. Allah, may He be exalted,
says (interpretation of the meaning):
"Say: O 'Ibaadi (My slaves) who have transgressed against themselves
(by committing evil deeds and sins)! Despair not of the Mercy of
Allaah, verily, Allaah forgives all sins. Truly, He is Oft-Forgiving,
Most Merciful"
[al-Zumar 39:53].
It was narrated from AbuMoosa (may Allah be pleased with him) that the
Prophet (blessings and peace of Allah be upon him) said: "Allaah holds
out His hand at night to accept the repentance of those who have
sinned during the day, and He holds out his hand by day to accept the
repentance ofthose who have sinned at night - until the sun rises from
its place of setting."
Narrated by Muslim, 2759
You have to repent and do a lot of righteous deeds. With regard to
thinking about whether this was done in a state of anger or not, this
comes under the heading of waswasah (whispers from the Shaytaan), who
wants todivert you from repentance or weaken your fear of Allah and
your efforts to do righteous deeds. If you understand the abhorrent
nature and seriousness of what you did, that impels you to strive to
do good and to instil in your heart humility before Allah; it makes
you pin your hopes on His grace, kindness and pardon. But if your nafs
makes falsehood attractive to you and detracts from the seriousness of
the crime by claiming that it happened in a moment of anger, then this
will weaken you resolve and distract you from turning to Allah.
It should be noted that anger is not an excuse inall cases; rather the
anger that may excuse a person is anger in whichhe loses his ability
of discernment to the extent that he does not know what he is saying.
If this happened once, it does not happen repeatedly. Many of those
who have the problem of reviling Islamcould never revile their fathers
or someone they hold in high esteem or the father of an opponent in an
argument and the like, no matter how angry they become, but they do
revile the religion because their hearts are devoid of faith and they
are lacking in respect towards Allah, His Messenger and His religion.
We ask Allah to keep us safe and sound. If there was any faith in his
heart it would prevent him from reviling religion.
So ignore this waswaas (whisper). You have committed a grave sin, but
you have a Lord Whois Most Merciful, Most Generous, Who accepts
repentance of the one who repents, forgives sins, and replaces evil
deeds with good deeds. So prepare to strive hard, fill your heart
withveneration and respect towards Allah, may He beexalted, and His
religion,read a lot of Qur'aan anddo a lot of righteous deeds.
We ask Allah to accept your repentance and forgive your sin.
And Allah knows best.