Let the debtor of the ten thousand talents in the Gospel be an example to you.
If you do not forgive the person who has harmed you, neither will you attain the absolution of your sins; because the Gospel says of the debtor of the ten thousand talents who did not forgive his debtor that “he was delivered to his torturers” (Matt. 18:24-35).
It is appropriate that you do not pray only for yourself, but also for every fellowman, so that in this way, you will be emulating the angelic manner of praying.
Do not be sorrowed if you do not immediately receive from God that which you asked for, because He desires to benefit you even more through your patient perseverance in prayer.
Indeed, what is superior to associating with God and conversing with Him?
In wishing to teach His disciples that they must always pray and not be discouraged, the Lord narrated an appropriate parable (Luke 18:1-8).
In this parable a certain unfair judge said the following about a widow who was persistently demanding to be vindicated: “Even if I neither fear God nor feel any shame before people, however, because this woman continuously bothers me and demands to be vindicated, I shall do so.”
And the Lord then concluded: “So also shall God soon fulfill the wish of those who beseech Him day and night.”
That is, therefore, why you should not be discouraged or worried because you did not receive it, because you will receive it later. Be happy and persist, enduring the toil of holy prayer.
Overlook the needs of the body when you pray, so that you do not lose the greater gain of your prayer from the sting of a mosquito or the buzzing of a fly.
If you have diligence in prayer, be prepared for attacks by demons and endure their blows with bravery, because they shall charge at you like wild beasts, to torment you.
He who suffers sorrowful things will also attain joyful ones. He who perseveres during unpleasant things will also enjoy pleasant ones.
Nilus the Ascetic of Sinai (d. c.430): On Prayer, trans. Holy Monastery of the Paraklete Oropos, Attica (Greece).