And take the sword of the Spirit, which is the word of God… – Ephesians 6:17

A sword is a weapon which may do hurt to the man who flourishes with it in mere wanton pride. No one can handle the sword of the Spirit aright save the chosen man whom God hath ordained from before the foundation of the world, and trained in feats of arms. By this the elect of God are known-that they love the Word of God, and they have a reverence for it, and discern between it and the words of man… God’s own people have discernment to discover and relish God’s own Word. They will not be misled by the cunning craftiness of human devices. Saints know the Scriptures by inward instinct. The holy life, which God has infused into believers by His Spirit, loves the Scriptures, and learns how to use them for holy purposes… In the things of the Word we are dunces till we enter the school of the Holy Ghost. He must take of the things of Christ, and show them unto us. He must teach us how to grip this sword by faith, and how to hold it by watchfulness, so as to parry the adversary’s thrust, and carry the war into the foeman’s territory. He is well taught who can swing this great two-handed sword to and fro, and mow a lane through the midst of his opponents, and come out a conqueror at the end. It may take a long time to learn this art; but we have a right skillful Teacher. Those of us who have been in this warfare thirty or forty years feel that we have not yet reached the full use of this sword; nay, I know for one, that I need daily to be taught how to use this mysterious weapon, which is capable of so much more than I have yet supposed. It is the sword of the Spirit, adapted for the use of an Almighty arm, and therefore equal to the doing of far more than we think. Holy Spirit, teach us now feats of arms by this Thy sword! ! C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/2201.cfm