The faith and love of the believer have their ebb and flow. They are subject to all sorts of fluctuation, but the security of the believer rests in the faithfulness of God and in the fact that the covenant of his peace will not be removed (Isaiah 54:10)… It is upon the determinativeness and stability of God’s gifts that our hearts must rest if we are not to be driven about by the fluctuating tempers or temperatures of our own experience. From a different angle it may be much the same thing to say that it is in Christ Jesus that all the promises of God are yea and amen, and he is the same yesterday, today, and forever. There is no fluctuation in his faithfulness and it is because of him that they are sure to us.
Via: The 9Marks Blog