The book of Hebrews is forward looking.
To a people who are suffering for their faith, he has little to offer them of present encouragement. He does not know when their trials will be over – unless, of course, you want to talk about death. But for the unfaithful, trials do not end with death, for they will one day stand before God to be judged.
And yet, there is hope.
The writer talks about it in terms of the “rest” of God. It is obviously not a rest that occurs in this life. It looks beyond this life to the one to come. But that rest comes only to those who make every effort to be obedient to God, trusting that His way is the only way to live with any promise at all.
Like ancient Israel, we as Christians, because of our faith in Christ, have entered that lot of people who have been qualified by God to share in His rest. But like ancient Israel, we can lose our share in that rest if we turn from faith . . . and The Faith (note 4:13).