The Silent Battle Within: Guarding the Heart with St. Isaiah of Gaza
The passions (here I mean the word in the negative sense, our irrational passions) do not grow weaker as we age. They grow subtler. Pride can disguise itself as maturity. Despair can look like realism. Sloth can look like prudence and balance, and so on. This is why we must pray constantly for God's help and mercy. These disordered impulses, left unchecked, cloud the mind and draw the heart away from God. The work of guarding the heart is never finished, not until our final breath.
“I entreat you not to leave your heart unguarded, so long as you are in the body. Just as a farmer cannot feel confident about the crop growing in his fields, because he does not know what will happen to it before it is stored away in his granary, so a man should not leave his heart unguarded so long as he still has breath in his nostrils. Up to his last breath he cannot know what passion will attack him; so long as he breathes, therefore, he must not leave his heart unguarded, but should at every moment pray to God for His help and mercy.” - St Isaiah the Solitary
The one who ceases to ask for help has already begun to lose the battle.
The saints understood that spiritual warfare is not a seasonal exercise. It is not confined to youth, or to moments of crisis. It persists until death, and only at death is the struggle concluded. This is why the desert fathers and saints, though often appearing serene and detached from worldly affairs, were inwardly aflame with the urgency of battle.
Their peace was not passivity but vigilance anchored in trust.
To guard the heart is to be attentive to the good God who is at all times and in all places attentive to us. It is to recognize that the soul, like a field, is always in danger until it is finally stored away in God. Let us then not grow weary in the work of watchfulness, nor grow careless in times of calm. As St. Isaiah teaches, we must be as men who have never finished sowing, never ceased weeding, and never abandoned the field until the Master Himself gathers the harvest.
“Lord Jesus Christ, Son of God, have mercy on me, a sinner.”