I understand that the Jesus prayer is much loved by the Orthodox Church. I love it.
It is packed with theology
Lord Jesus Christ, Son of God,
Be merciful to me, a sinner.
Working backwards: I, like all my fellow men, am a sinner. The concept of Original Sin is absolutely fundamental to Christianity/Catholicism. We know the difference between Good and Evil – and we know that we do Evil. Read a newspaper; examine your conscience. To acknowledge Original Sin is the beginning of Wisdom.
We therefore require Mercy.
We appeal to Christ for Mercy. We acknowledge that the historical Jesus is the Christ – the Son of God, the Lord of Creation.
A hundred times a day – not nearly enough.