12 And it was because of the pride of their hearts, because of their exceeding riches, yea, it was because of their oppression to the poor, withholding their food from the hungry, withholding their clothing from the naked, and smiting their humble brethren upon the cheek, making a mock of that which was sacred, denying the spirit of prophecy and of revelation, murdering, plundering, lying, stealing, committing adultery, rising up in great contentions, and deserting away into the land of Nephi, among the Lamanites—
13 And because of this their great wickedness, and their boastings in their own strength, they were left in their own strength; therefore they did not prosper, but were afflicted and smitten
Prosperity leads us to believe in our own strength and ability and can tempt us to think that we are prosperous because we have "earned" it. We can forget the Lord and his goodness, including the talents and abilities he has given us that enabled our prosperity to begin with. Humbling facing adversity with faith in and dependence upon the Savior can build and strengthen us for even greater challenges. Pride leaves us "in [our] own strength." We need power today and hope in the future. That comes from trusting in God. There is no lasting hope in work, politics, diplomacy, or any other worldly pursuit. But there is hope that comes through the power of the atonement and the love of the Savior.
Elder W. Craig Zwick said in October General Conference in 2003:
"Every one of us needs to know that we can go on in the strength of the Lord. We can put our hand in His, and we will feel His sustaining presence lift us to heights unattainable alone. . .
If we will keep the commandments of God and walk hand in hand with Him in His paths, we will go forward with faith and never feel alone.
Trust in His promise of eternal life, and allow peace and hope to distill upon you.
When we connect with the Author of Peace and with His perfect and redeeming love, then we can come to know the reality of the Lord’s promise: “I the Lord thy God will hold thy right hand, saying … , Fear not; I will help thee” (Isa. 41:13)."