On being mindful of death

Die daily, that you might live eternally, for one who fears God will live forever.

Venerable St. Anthony the Great

After death, it will be impossible for anyone through thoughts of God to heal the sickness brought on by sin, for confession has power on earth, but not in hell.

Holy Hierarch St. Gregory of Nyssa

To teachers of wisdom, it was not accidental that death entered our life, to instruct the intellect, to tame the passions of the soul, to calm the waters, and to establish calm.

Holy Hierarch St. John Chrysostom

Salvific for us and deadly for sin is the remembrance of death which was born of sin. 

Holy Hierarch St. Ignaty Brianchaninov