Nothing in this life is eternal. Nothing shall last forever. For good or bad, everything shall pass away.
Find comfort and peace in that, for if you are afflicted or if something is bad and ails you, it will not last forever, so endure with patience. There will be a day when you are free from that negative affliction.
And if there be something good you desire, but it eludes you and leaves you feeling forsaken or distraught you cannot claim it, be at peace for it too shall one day fade away.
Only one thing is eternal; and that is God. Seek Him and His joy, for everything else shall fade away. All the things of this world, whether for good or bad, are temporal and will one day cease, so while we may seek after good things, do not be broken in spirit when they do not find their way to you, for they are a temporary thing.