Legalists say, you cannot keep this 24/7 and if you fail once you deny Jesus and lose your salvation.
They then say, no grace says all sin is removed, faith alone is everything.
I would say that legalists say that you can keep this 24/7.
That is why they are called legalists
Or as some like to say "Pharisees"
Those who say you cannot keep 24/7 I would say are realist's.
That does not necessarily mean that they want to sin but know they can sin.
I'm not aware of anyone here who you define as legalists have said "If you fail once and deny Jesus then you lose your salvation"
What I have seen is that they say "You break one law then you break them all"
Maybe by inference or infact said "If you rely on 24/7 keeping to be saved and yet do not then by your definition you have lost your salvation"
What I have found is that those I would define as legalists (hard core ones) when challenged about sin, the sin of omission or unknown sins they excuse this as being "I did no I sinned therefore it does not count"
To me that's a very lame excuse.
Sin is sin.
Everyone of us should be seeking God to reveal in us when we have sinned but don't know we have.
The goats ask Jesus "When did we?
Jesus replies “I tell you the truth, whatever you did not do for one of the least of these, you did not do for me"
The fact is that grace covers all sin and faith alone is everything.
Paul addressed this in Romans.
Yes where sin abounds so does grace, but for goodness sake don't use it as an excuse to sin. That's not the purpose of grace.
It's purpose is to set you free from it.
Ephesians 2:8-10
8 For by grace you have been saved through faith, and that not of yourselves; it is the gift of God, 9 not of works, lest anyone should boast. 10 For we are His workmanship, created in Christ Jesus for good works, which God prepared beforehand that we should walk in them.
Romans 8:28-30
28 And we know that all things work together for good to those who love God, to those who are the called according to His purpose.
29 For whom He foreknew, He also predestined to be conformed to the image of His Son, that He might be the firstborn among many brethren. 30 Moreover whom He predestined, these He also called; whom He called, these He also justified; and whom He justified, these He also glorified.