Psalms 90:15

Make us glad according to the days wherein thou hast afflicted us - Let the one correspond with the other. Let our occasions of joy be measured by the sorrows which have come upon us. As our sufferings have been great, so let our joys and triumphs be.

And the years wherein we have seen evil - Affliction and sorrow. They have been continued through many wearisome years; so let the years of peace and joy be many also.