As beautiful as is a rainbow, it is not permanent. It passes away and is no more.
The Christian character must not resemble the rainbow in its transitory beauty, but, on the contrary, must be established, settled, and abiding. Seek, O believer, that every good thing you have may be an abiding thing.
May your character not be a writing upon the sand, but an inscription upon the rock! May your faith be built of material able to endure the awful fire which shall consume the wood, hay, and stubble of the hypocrite. May you be rooted and grounded in love. May your convictions be deep, your love real, your desires earnest. May your whole life be so settled and established that all the storms of earth shall never be able to move you.
To be established in faith, there will be suffering. There is no use to hope that we shall be well rooted if no rough winds pass over us. Those old gnarlings on the root of the oak tree, and those strange twistings of the branches, all tell of the many storms that have swept over it, and they are also indicators of the depth into which the roots have forced their way.
So the Christian is made strong, and firmly rooted by all the trials and storms of life. Shrink not then from the tempestuous winds of trial, but take comfort, believing that by the rough discipline God is fulfilling this benediction to you.
From: Morning and Evening by Charles Spurgeon