After I was saved from the death penalty that hangs over us all, I memorized a different translation of this verse very early on:

For God is not unjust so as to overlook your work and the love that you have shown for his name in serving the saints, as you still do. And we desire each one of you to show the same earnestness to have the full assurance of hope until the end, so that you may not be sluggish, but imitators of those who through faith and patience inherit the promises. Hebrews 6:10-12 English Standard Version (ESV)

This is a key verse of assurance. Self-sacrifice in service to our brothers and sisters is both a marker and builder of our confidence in His promise of eternal life. And that service is not directed only to those professing faith, but those especially; while not forgetting our duty for service to all.

Every day shows us how futile this world is. Our faithful actions can show us to have a different destiny.

What does Calvin say about the passage here and here?

For God is not unrighteous, etc. These words signify as much as though he had said, that from good beginnings he hoped for a good end.

But here a difficulty arises, because he seems to say that God is bound by the services of men: “I am persuaded,” he says, “as to your salvation, because God cannot forget your works.” He seems thus to build salvation on works, and to make God a debtor to them…

…God does not pay us a debt, but performs what he has of himself freely promised, and thus performs it, inasmuch as he pardons us and our works; nay, he looks not so much on our works as on his own grace in our works. It is on this account that he forgets not our works, because he recognizes himself and the work of his Spirit in them…

…God is righteous in recompensing works, because he is true and faithful: and he has made himself a debtor to us, not by receiving anything from us; but as Augustine says, by freely promising all things.

And labor of love, etc. By this he intimates that we are not to spare labor, if we desire to perform duty towards our neighbors; for they are not only to be helped by money, but also by counsel, by labor, and in various other ways. Great [diligence], then, must be exercised, many troubles must be undergone, and sometimes many dangers must be encountered. Thus let him who would engage in the duties of love, prepare himself for a life of labor…

By saying that they had ministered and were still ministering, he commended their perseverance; which in this particular was very necessary; for there is nothing to which we are more prone than to weariness in well doing. Hence it is, that though many are found ready enough to help their brethren, yet the virtue of constancy is so rare, that a large portion soon relax as though their warmth had cooled.

But what ought constantly to stimulate us is even this one expression used by the apostle, that the love shown to the saints is shown towards the name of the Lord; for he intimates that God holds himself indebted to us for whatever good we do to our neighbors, according to that saying,

“What you have done to one of the least of these, you have done to me,” (Matthew 25:40)

and there is also another,

“He that gives to the poor lends to the Lord.” (Proverbs 19:17).

And we desire, etc…“You have made,” he says, “your love evident by many acts of kindness; it remains, however, that your faith should correspond with it; you have [diligently] labored not to be wanting in your duties to men; but with no less earnestness it behooves you to make progress in faith, so as to manifest before God its unwavering and full certainty.”

Now, by these words the Apostle shows that there are two parts in Christianity which correspond with the two tables of the Law…Let us then remember, that the life of a Christian is not complete in all its parts, unless we attend to faith as well as to love.

To the full assurance of hope, or, to the certainty of hope, etc. As they who professed the Christian faith were distracted by various opinions, or were as yet entangled in many superstitions, he bids them to be so fixed in firm faith, as no longer to vacillate nor be driven here and there, suspended between alternate winds of doubts. This injunction is, however, applicable to all; for, as the truth of God is unchangeably fixed, so faith, which relies on him, when it is true, ought to be certain, surmounting every doubt. It is a full assurance, πληροφορία, an undoubting persuasion, when the godly mind settles it with itself, [which] it is not right to call in question what God, who cannot deceive or lie, has spoken…

But followers, or imitators, etc. To sloth he opposes imitation; it is then the same thing as though he said, that there was need of constant alacrity of mind; but it had far more weight, when he reminded them, that the fathers were not made partakers of the promises except through the unconquerable firmness of faith; for examples convey to us a more impressive idea of things…

Faith and patience, etc. What is meant is, a firm faith, which has patience as its companion. For faith is what is, chiefly required; but as many who make at first a marvelous display of faith, soon fail, he shows that the true evidence of that faith which is not fleeting and evanescent, is endurance. By saying that the promises were obtained by faith, he takes away the notion of merits; and still more clearly by saying that they came by “inheritance”; for we are in no other way made heirs but by the right of adoption.

Beautiful Scandalous Night from Flap Your Wings by The Choir