For all the promises of God in Him are yea, and in Him Amen, unto the glory of God by us. – 2 Corinthians 1:20 

The Christian man can go away with the reflection that his battlements can never be taken away, because they are the Lord’s. We rely upon the electing love of Jehovah-Father, Son, and Holy Ghost; we trust in the redeeming blood of Jesus Christ, the Everlasting Son; we depend wholly upon the merits, blood, and righteousness of Jehovah-Tsidkenu-the Lord our righteousness; we are confiding in the Holy Spirit. We confess that we are nothing of ourselves-that it is not of him that willeth, or of him that runneth, but of God that showeth mercy. We do not acknowledge one scrap of the creature in our salvation nor one atom of self; we rely entirely upon covenant love, upon covenant mercy, covenant oaths, covenant faithfulness, covenant immutability, and resting on these, we know our battlements cannot be taken away. Oh, Christian! with these walls surrounded thou mayest laugh at all thy foes. Can the devil touch thee now? He shall only look upon thee and despair. Can doubts and fears take away our battlements? No: they stand fast and firm, and our poor fears are but as straws dashed against the wall by the wind; for, “though we believe not, yet He abideth faithful,” and not all the temptations of a sinful world, or our own carnal hearts, can separate us from the Saviour’s love. We have a city, the walls of which are mighty, the foundations of which are eternal; we have a God who says, “I the Lord do keep her, and do water her every moment, lest any hurt her, I will keep her day and night.” Trust Christian, here, salvation shall God appoint for walls and bulwarks. Surrounded with these, thou mayest smile at all thy foes. But take heed you add nothing to them, for if ye do, the message will be, Take away the battlements, they are not the Lord’s.” ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0038.cfm