You cannot approach God without constant prayer.
St Isaac the Syrian (d. 700) in Writings from the Philokalia
...it is the duty of all Christians, small and great, always to practice the mental prayer Lord Jesus Christ, have mercy on me, so that their mind and heart may acquire the habit of always uttering those holy words. Let this convince you how pleasing this is to God and what great good derives from it, since He, out of His infinite love for men, sent a heavenly Angel to tell us this, so that no one should have any doubt about it.
St. Gregory Palamas (d. 1359) relating an Angel of God's revelation in the Life of St. Gregory of Salonica
I made him (unruly godson) sit down on a bench next to me and I ordered him to say the Jesus Prayer without stopping...After some time I noticed the whip was no longer necessary, for the boy recited the Prayer willingly and diligently and I noticed a change in his behavior...he got so accustomed to the the Prayer that he was saying it no matter what he was doing...
Told to the anonymous author of The Way of a Pilgrim (19th century Russia); chapter 4
By it the heart is opened to human wretchedness and the Savior's mercy. The invocation of the holy name of Jesus is the simplest way of praying always. When the holy name is repeated often by a humbly attentive heart, the prayer... "brings forth fruit with patience. This prayer is possible "at all times" because it is not one occupation among others but the only occupation: that of loving God, which animates and transfigures every action in Christ Jesus.
1994 Catechism of the Catholic Church sections 2667-2668
