These short prayers are known as "arrow" prayers: little reminders during the day that we are always in the presence of the Father.
The following eight “arrow” prayers are attributed to St. John Chrysostom. The description arrow prayers refers to short, frequent thoughts that we direct to God, as a reminder that we are constantly in his presence, and to call down his grace.
In the long tradition of the Church, various names have been given to these short prayers — our little hellos — that we speak to Our Lord throughout the day. They are called aspirations, or ejaculatory prayers (from the Latin for bursting forth), or as well, “arrow” prayers.
This last title was used by Padre Pio when he described these short, spontaneous prayers. He said they are like “arrows that wound God’s heart.”
Here are eight from John Chrysostom:
O Lord, enlighten my heart that evil desires have darkened. O Lord, send down Thy grace to help me, that I may glorify Thy name. O Lord Jesus Christ, write me in the book of life and grant unto me a good end. O Lord, sprinkle into my heart the dew of Thy grace. O Lord, quicken in me a good thought. O Lord, give me tears and remembrance of death, and contrition. O Lord, implant in me the root of all good: Thy fear in my heart. O Lord, grant that I may love Thee from all my soul and mind, and in everything do Thy will.
Padre Pio says God is “obliged” to answer this type of prayer