Stephen Charnock wrote an excellent tome on “The Existence and Attributes of God.” This work is full of rich truth of great benefit to the Christian. For your edification I am going to periodically post heavily edited excerpts from Charnock’s work.
If God is unchangeable in doing us good, it is reasonable we should be unchangeable in doing Him service. If He assures us He is our God, our “I Am,” He desires also that we should be his people. If God is constant in keeping his promises, He expects we should be constant in our obedience. As His spouse, we should be unchangeably faithful to him as a Husband; as subjects we should have an unchangeable allegiance to him as our Prince. He would not have us be faithful to him for an hour or a day, but “to the death” (Rev. 2:10). It is reasonable we should be His, and if we be His children, we should imitate Him in His constancy of His holy purposes.
Unchangeableness in faithfulness is our glory and gain. To be a reed shaken with every wind is not praiseworthy among men, and it is less a ground of praise with God. It was Job’s glory that he held fast his integrity (Job 1:22): “In all this Job sinned not;” in all this,—which whole cities and kingdoms would have thought justification enough of loud complaints against God, and also against the temptation of his wife. In all this he retained his integrity (Job 2:9). The devil, who by God’s permission stripped Job of his goods and health, could not strip him of his grace. As a traveller, when the wind and snow beats in his face, wraps his cloak more closely about him to preserve that and himself so Job wrapped his confidence in God more closely about him. Better we had never made profession, than afterwards to abandon it. A wilting profession serves no other use than to aggravate our sin. What profit will it be to a soldier, if he hath withstood many assaults, and turn his back at last? If we would have God crown us with an unchangeable crow, we must crown our beginnings with a happy perseverance (Rev. 2:10).