If you put something fragrant on to burning coals, you motivate those who approach to come back again and to stay near, but if instead you put on something with an unpleasant, oppressive smell, you repel them and drive them away.
It is the same with the mind. If your attention is occupied with what is holy, you make yourself worthy of being visited by God, since this is the sweet savour which God catches scent of.
On the other hand, if you nurture evil, foul and earthly thoughts within you, you remove yourself from God’s supervision and unfortunately make yourself worthy of His aversion.
We know that prayer in and of itself cannot save us, but carrying it out before God can.
For when the Lord’s eyes are upon us He sanctifies us, as the sun warms everything upon which it shines.
~ St. Gregory Palamas
St Vasilios Greek Orthodox Church 