What Oxygen is for our Physical well-being, God's Grace is for our Spiritual ( Elder Paisios )
"You must know that only passions and sins are ours. Whatever good we do is from God, whatever foolish things we do come from us. When God's Grace abandons us for just a little while, we become unable to do anything. As in natural life, when God removes oxygen from us we die immediately. The same is true for spiritual life: If God removes His Grace, we are lost."
Elder Paisios