The LORD's purposes throughout history never have been, never are, and never will be thwarted. The LORD has never been discouraged, never lost hope, never been slowed.
For me personally, this means that my stubbornness, my moral failures, my inabilities, my weaknesses, and all my sins are not a discouragement to the LORD. The LORD is not even moved an inch in his righteousness. If God himself is not discouraged and his purpose for me will continue through even the worst of my sin, I have eternal hope in his righteousness. When I am discouraged, I can count on his own righteousness in Christ to be my satisfaction (Matthew 5:6).
And for all the evil in this world, for all its suffering and death, for the mental illness, the disobedience of children, the hardness of hearts, the rejection of his Son, and even the very crucifixion of his son, the LORD's righteousness is never moved. His righteousness is not dismayed. No, it endures forever (Isaiah 51:8).
Through Christ's righteousness, his salvation is for us. His salvation is past the existence of our own lives, past the existence of this present physical earth, which will continue to break down like a garment, piece by piece, thread by thread until it cannot support us and gives way. His salvation supersedes the heavens, which will vanish like smoke. And this salvation is for us and will exist long after all that we can see is gone.
Christian, do not be dismayed. The LORD's righteousness is forever and it is our satisfaction! His salvation is forever and it is for us!