You need endurance to do the will of God and receive what he has promised.
The Greek noun translated here as simply endurance is often translated as "cheerful endurance." This is not a teeth gritting endurance but a peaceful passing through with firm hope and trust that on the other side of the painful experience there is light.
In our world of immediacy, it is worthwhile to stop and remember the cardinal virtue of fortitude.
As the Catechism says:
Fortitude is the moral virtue that ensures firmness in difficulties and constancy in the pursuit of the good. It strengthens the resolve to resist temptations and to overcome obstacles in the moral life. The virtue of fortitude enables one to conquer fear, even fear of death, and to face trials and persecutions. It disposes one even to renounce and sacrifice his life in defense of a just cause. "The Lord is my strength and my song." "In the world you have tribulation; but be of good cheer, I have overcome the world."
From the small daily bumps in the road, to the large crises, he answer is the same. We keep our eyes fixed on the loving face of God, and walk forward through life one step at a time.