Albert Barnes Commentary Hebrews 10:36

"For ye have need of patience, that, having done the will of God, ye may receive the promise." — Hebrews 10:36 (ASV)

For you have need of patience. They were then suffering, and in all trials we have need of patience. We have need of it because there is in us so much disposition to murmur and fret; because our nature is liable to sink under sufferings; and because our trials are often protracted. All that Christians can do in such cases is to be patient—to lie calmly in the hands of God, and submit to his will day by day, and year by year. See James 1:3-4; see also the notes on Romans 5:4.

That after you have done the will of God. That is, in bearing trials, for the reference here is particularly to afflictions.

You might receive the promise. The promised inheritance or reward—in heaven. It is implied here that this promise will not be received unless we are patient in our trials, and the prospect of this reward should encourage us to endure them.