Here is verses 9 to 12.
1st Who is this written to? Christians not unbelievers.
2nd You will notice in the ending of verse 11 "eagerness to the full assurance of the hope to {the} end,"
If OSAS was true there is no need for the Hebrew writer to say "even holding fast salvation" in verse 9 and "eagerness to the full assurance of the hope to {the} end" in verse 11. If you can't lose something then there is no need to hold fast onto it to the end. May special attention to verses 11 and 12.
9.
|3982| we have been persuaded
|1161| But
|4012| about
|5216| you,
|0027| loved ones
|3588| the things
|2909| better,
|2532| even
|2192| holding fast
|4991| salvation,
|1499| if indeed
|3779| so
|2980| we speak.
10.
|3756| not
|1063| Because
|0094| unjust
|3588| -
|2316| God
|9999| {is}
|1950| to be forgetful
|3588| of the
|2041| work
|5216| of you,
|2532| and
|0026| of love
|3739| which
|1731| you showed
|1519| to
|3588| the
|3686| Name
|0846| of Him,
|1247| having ministered
|3588| to the
|0040| holy ones
|2532| and
|9999| {now}
|1247| are ministering.
11.
|1937| we desire
|1161| But
|1538| each one
|5216| of you
|3588| the
|0846| same
|1731| to show
|4710| eagerness
|4314| to
|3588| the
|4136| full assurance
|3588| of the
|1680| hope
|0891| to
|9999| {the}
|5056| end,
12.
|2443| lest
|3361| not
|3576| lazy
|1096| you become
|3402| imitators
|1161| But
|3588| of those
|1223| through
|4102| faith
|2532| and
|3115| long-suffering,
|2816| inherit
|3588| the
|1860| promises.
You should have noticed in verse 11 to 12 that verse 11 isn't the ending of the thought. The thought carries into verse 12. Here it is without verses the way it was orginally written. This might help you understand it better.
But we desire each one of you the same to show eagerness to the full assurance of the hope to {the} end, lest not lazy you become imitators.
But of those through faith and long-suffering, inherit the promises.
|1161| But
|1937| we desire
|1538| each one
|5216| of you
|3588| the
|0846| same
|1731| to show
|4710| eagerness
|4314| to
|3588| the
|4136| full assurance
|3588| of the
|1680| hope
|0891| to
|9999| {the}
|5056| end,
|2443| lest
|3361| not
|3576| lazy
|1096| you become
|3402| imitators
|1161| But
|3588| of those
|1223| through
|4102| faith
|2532| and
|3115| long-suffering,
|2816| inherit
|3588| the
|1860| promises.
But we desire each one of you the same to show eagerness to the full assurance of the hope to {the} end, lest not lazy you become imitators.
But of those through faith and long-suffering, inherit the promises.
We shouldn't become lazy to what?
We then become imitators of those who didn't enter into His rest from chaper 4?
But of those through faith and long-suffering, inherit the promises.
What promise? Salvation!