steadfast endurance: holding one's ground in faith under pressure, sustained by hope in God
The word is built from two parts that together mean a remaining under, the picture of a soldier who stands his ground instead of breaking and running. But the New Testament writers did not borrow this word for grim, gritted-teeth toughness, and they did not mean the mild, passive thing we usually call patience. They meant something active and forward-leaning: the kind of holding firm that keeps going precisely because it expects God to make things right in the end.
That hopeful coloring came from the Greek Old Testament, where this word and its verb were used again and again to translate Hebrew words for waiting on God and hoping in him. So by the time the New Testament writers picked it up, the word already carried trust in God built into it. Endurance here is hope lived out over time under hard conditions, not self-reliant willpower.
The senses below are not different meanings but the same virtue seen from different angles: the way a believer holds firm under affliction, endurance named as a settled quality of Christian character to be pursued, and the endurance that comes from God and is patterned on Christ's own steadfastness. One word ties them together because, for these writers, all three are the same thing: faith and hope holding their ground when life pushes back.