Hebrews 3:19
“So we see they could not enter because of “unbelief.”
The sin of Hebrews 3 is unbelief. The only thing that kept the children of Israel from the promise land was their lack of faith. Likewise the only sin, which will keep us from all that God has for us is, unbelief.
The Truth
“Most assuredly, I say to you, he who believes in Me has everlasting life.” (John 6:47)