Why Do PBs Sing This Song?

In the song "Home Of The Soul" and sung by PBs (here) we find them singing these words.

If for the prize we have striven,
After our labors are o’er,
Rest to our souls will be given,
On the eternal shore.

Refrain

Home of the soul, beautiful home,
There we shall rest, never to roam;
Free from all care, happy and bright,
Jesus is there, He is the light!

Oft, in the storm, lonely are we,
Sighing for home, longing for Thee,
Beautiful home of the ransomed,
Beside the crystal sea.

Refrain

Yes, a sweet rest is remaining
For the true children of God,
Where there will be no complaining,
Never a chastening rod.

Refrain

Soon, the bright homeland adorning,
We shall behold the glad dawn;
Lean on the Lord till the morning,
Trust till the night is gone.

If for the prize we have striven, after our labors are over, we shall enter into rest? Do you see how these words are not believed by today's Hardshells? Do they teach that one must strive and labor for the prize, for the rest that is Heaven? The word "if" is so important. It implies a "then." If we have striven and labored and run for the prize (Phill. 3: 14), then we will enter into God's rest (unlike the Israelites who fell in the wilderness).

Hardshell apologist Jason Brown and I debated the issue of the "rest" of Hebrews chapters 3 and 4 and whether the words "let us labor therefore to enter into that rest" denoted entering into heaven.

See these postings

Lessons From Israelite Carcasses
Entering God's Rest
Entering God's Rest Conclusion
Resting From Christian Labor

But, it is no new thing that Hardshells sing songs that are contrary to their theology.