Abba Macarius the Great said, “Concentrate in this name of our Lord Jesus Christ with a contrite heart, the words welling up from your lips and drawing you to them. And do not depict Him with an image in your mind but concentrate on calling to Him: ‘Our Lord Jesus, have mercy on me.’ Do these things in peace and you will see the peace of His Divinity within you; He will run off the darkness of the passions that dwell within you and He will purify the inner person [2 Cor 4:16, Eph 3:16] just as Adam was pure in paradise. This is the blessed Name that John the Evangelist pronounced: ‘Light if the world and unending sweetness, the food of life and the true food'” (Jn 6:48, 6:55, 8:12)
From The Virtues of Abba Macarius the Great