The Holy Spirit is like our General in this war, and the sharper the soldier, with readied weapons, the more powerfully He will be able to use us, with greater damage to the Enemy of our soul.
Of the weapons He has provided for doing battle, the sword of the Word and prayer are the ones for offense. The rest of the armor parts are for protection, for defense, but the Scriptures are to be wielded in attack, often through prayer.
Among the various ways and means that the spiritual soldier can gain and maintain a state of readiness, sword continually sharpened, memorization of the Word is the best.
Psalm 119:11 provides the most basic, foundational motive for memorizing the Scriptures --- “Your word I have treasured in my heart, That I may not sin against You.” As Charles Spurgeon noted astutely, it is the best thing in the best place for the best purpose.
As a seasoned Seminary professor I admired once said, “It is amazing the affinity the Holy Spirit has for a trained mind.” In context he was encouraging Seminary training, but there is needed application related to Scripture memory, as well.
The more of the Bible that is lovingly stored away by the Christian soldier, the greater the ammunition available to the blessed Spirit for warfare.
And He is so faithful to bring to one’s remembrance a pertinent verse, or even part of one, at the exact time it is needed most. It would be grievous to know how many times we have succumbed to temptations, or acted un-biblically, or made foolish decisions simply because we didn’t know the Word.
Like Elisha’s servant in II Kings 6:17, may the Holy Spirit open our eyes to see the ongoing warfare that is happening in the spiritual realms even at this moment. Would that He would impress upon us the urgency of having un-rusted swords, by hiding His Word in our hearts for use at any given moment!