Be attentive to yourself, so that nothing destructive can separate you from the love of God. Guard your heart*, and do not grow listless and say: “How shall I guard it, since I am a sinner?” For when a man abandons his sins and returns to God, his repentance* regenerates him and renews him entirely.
~St Isaiah The Solitary (Philokalia, vol. 1, p. 26)
*Heart-the spiritual center of man’s being, his deepest and truest self, where man finds union with God.
*Repentance-a change of mind or intellect, involving sorrow, contrition and regret but more importantly the conversion of our whole being, and a turning to God.
With Christ all things are possible and there is always hope. Everyone has sinned, and likewise everyone can turn from sin towards God, and start anew. The enemy sows seeds of despair within us, when we see ourselves having sinned, imagining ourselves to be overwhelmed by our sin and without hope. But this is never the case, for we always have hope in Christ and can call upon Him out of the simplicity of our repentance.
For more on the power of repentance read, Turning the Heart to God by St Theophan the Recluse.
When the enemy insinuates sin into our heart we must be attentive to his suggestions, and on guard to resist him, by keeping our focus always on God. This is attentiveness, keeping watch over our thoughts and our fantasies, capturing them and bringing every one of them to the feet of Christ, as St Paul says, “For the weapons of our warfare are not carnal but mighty in God for pulling down strongholds, casting down arguments and every high thing that exalts itself against the knowledge of God, bringing every thought into captivity to the obedience of Christ, and being ready to punish all disobedience when your obedience is fulfilled” (2 Corinthians 10:4-6).
Lord Jesus Christ, Son of God, have mercy on me a sinner.