# standing at a distance

This was a sign of humility. He did not feel worthy to stand closer.

# would not even lift up his eyes to heaven

"would not even look up toward heaven"

# hit his breast

This is a physical expression of great sorrow, It shows this man's repentance and humility. Alternate translation: "hit his breast to show his sorrow"

# God, have mercy on me, a sinner

"God, please be merciful to me. I am a sinner" or "God, please have mercy on me even though I have committed many sins"