A fixed, constant attention to the promises, and a firm belief of them, would prevent solicitude and anxiety about the concerns of this life. It would keep the mind quiet and composed in every change, and support and keep up our sinking spirits under the several troubles of life…Christians deprive themselves of their most solid comforts by their unbelief and forgetfulness of God’s promises suitable to it, and abundantly sufficient for our relief in it.
A thorough acquiantance with the promises would be of greatest advantage in prayer. With what comfort may be the Christian address himself to God in Christ when he considers the repeated assurances that his prayers shall be heard! With how much satisfaction may he offer up the several desires of his heart when he reflects upon the texts wherein those very mercies are promised? And with what fervour of spirit and strength of faith may he enforce His prayers by pleading the several gracious promises which are expressly to his case!
– Samuel Clark, introduction to Scripture Promises
as quoted by J.I. Packer, Knowing God, copyright 1973, page 115