Webster(i)
15 While it is said, To-day if ye will hear his voice, harden not your hearts, as in the provocation.
16 For some, when they had heard, did provoke: yet, not all that came out of Egypt by Moses.
17 But with whom was he grieved forty years? was it not with them that had sinned, whose carcasses fell in the wilderness?
18 And to whom did he swear that they should not enter into his rest, but to them that believed not?
19 So we see that they could not enter in because of unbelief.