In my opinion only possibly, vs. 21 is very close to what Jesus said in Matthew 24......
13) But he that shall endure unto the end, the same shall be saved.
I don't see that verse as saying we have to work to see Heaven. Rather it is advising that when we endure in the word and trust God fully we shall overcome any challenge before us.
The works saves philosophy fails to realize from its inception it is insisting humans need assist Go with his divine plan of grace. And that Jesus dying on the cross wasn't really all that, or enough to fulfill that plan and set the new covenant into motion.
It's a notion that in some places is referred to as auto-theism, or auto-deism. "Self as god". As in, we're working to help God keep his word about saving us.
I think it qualifies as blasphemy of the highest order.
But those who think they have to work to keep themselves in God's good graces probably help out a lot of people with their labors. So, only when they're dead will they find the truth, at least while alive they served people while thinking they are important enough that God needs them to work hard so he'll keep his word.
