I used to be a Muslim and was taught about doing good deeds to get into heaven and about the angels on the right and left shoulder who count your good deeds and bad deeds and on the day of judgment the good and bad is weighed up. So when I came to Christianity and learnt about grace and Faith alone it was a big (and amazing) change for me.
Now today at our church outreach a Muslim man approached me seeing the colour of my skin and saw me with other Christians and asked me where I was from and wanted to know if I was a Muslim who's become a Christian. I was and so I told him. He started shouting and arguing with me then and not letting me get a word in, trying to use the verse about Jesus saying "I don't know you" to try and discredit Christianity somehow haha and when I tried to explain the actual meaning I spoke how it was about people who come to him with works and not with relationship and I started mentioning the main difference between islam and Christianity is that islam is work based salvation whereas Christianity is grace alone (he cut me off before I could fully explain the verse). This is when he tried to tell me it is not work based in islam and that he at the end of the day always relies on the mercy of God (I knew this was off but had no chance to defend or anything because he was talking over me at every single turn). And so afterwards on my own I started to look it up and it clearly stated in the Qur'an that good deeds and bad deeds will be weighed against each other, but it also says Allah is all forgiving, and in some of their other texts it says that sincere repentance would forgive all sins.
Now here's the thing. If Muslims argue that it ultimately relies on the mercy of God and not on deeds then it is a grace alone faith too, just like Christianity, however the more you think about it and know about Islam this isn't the case.
Muslims also believe they can never know whether they go to heaven or hell and so they live their lives not knowing and trying to do as much good and staying away from as much bad as possible in the hopes that they are good enough to go to heaven. There's multiple cases of this being the life Muslims lead and what they believe in their scriptures and you could literally ask any Muslim and at the end of the day this is how they live in their faith. They do believe Allah is all forgiving but at the same time they have no idea if they're going to be forgiven because it's up to Allah and they don't know what he will do, only he knows, and so they do their best to live as good and righteously as possible, hoping they're forgiven and go to heaven, and my friends this is not grace alone. This is a work based salvation plain and simple. They're always in fear of punishment and so work to live their best and most righteous lives on earth. If it was grace alone, and they relied ultimately and solely on the mercy of God then they would have a guarantee of salvation. So this guy, who didn't let me speak, left after saying a bunch of attacks against Christianity without hearing anything in return, and then came back and threatened me by saying if he saw me preaching there again in 10 minutes he'd hit me (I carried on for about 20-30 mins after and he never returned praise God. I also didn't even engage him at the start. Just told him I didn't want a debate when he was debating and was patient and listened.) This guy is lying about what islam believes or just doesn't have a full understanding of his own faith.
Christianity is the only faith that is truly salvation through faith and grace ALONE. That is why we have the guarantee of salvation which is a gift of God.
(This also does bring up a big contradiction in the crux of the islamic faith: If you know God is all forgiving and will forgive all sins through repentance you should actually know you are going to heaven... But that is not what I was intending to talk about in this message. Just wanted to talk about whether Islam was grace alone or work based.)