Helaman 15

10 And now, because of their steadfastness when they do believe in that thing which they do believe, for because of their firmness when they are once enlightened, behold, the Lord shall bless them and prolong their days

What does it mean to be steadfast? It means to be loyal in the face of trouble and difficulty. It means to be firmly determined or resolute - not shakable. It is to have unswerving devotion and to be unbendable. I think of the great granite monoliths of Yosemite Valley. I know they are susceptible to erosion and spalling, but they face the continuous action of wind and weather resolutely grand and firm. In our lives, the great test is whether we can remain resolutely determined to follow Jesus Christ no matter what comes our way. Can we love Him and follow Him in trial and when blessed beyond measure.

Paul wrote to the Colossians (Col. 2):

5 For though I be absent in the flesh, yet am I with you in the spirit, joying and beholding your order, and the stedfastness of your faith in Christ.
6 As ye have therefore received Christ Jesus the Lord, so walk ye in him:
7 Rooted and built up in him, and stablished in the faith, as ye have been taught

I like the image of roots. When we are deeply rooted in Him, as we have been taught, no temptation or trial can overcome our faith and bring us to despair.