Often our English words have already been charged with meaning before they are borrowed to explain the truths of Faith. This leads to confusion. Often we use the same words, but mean different things by them.
Remember the childhood game in which one child pulls back the fingers of another until the contorted child can no longer take the discomfort? The child yells out in a panic, “Mercy!” In English we often think of the petition for mercy as begging God to show us His love and compassion, asking Him to stop doing whatever it is that is making us uncomfortable. But that is not what mercy means, at least not within the Orthodox mindset.
Eleison literally translates into an image of one pouring oil on a wound. In the ancient world olive oil was treasured for its medicinal properties and was used on the both the sick and wounded. Recall the parable of the Good Samaritan. The wounds of the man lying half-dead were bandaged and anointed with oil by the compassionate Samaritan man. When we pray Kyrie elesion me, we are asking God to pour His healing Grace on our wounds and heal us. We are asking God to make us whole. Are we not the man lying half-dead in sin, waiting for the Physician of our souls to heal us of the great disease of sin?
Lord, Jesus Christ, Son of God, heal me with the balm of your Love because I am wounded. That is the Jesus Prayer.
Read it all here.