Why God Answers Some Prayers and Not OthersThe teachings of Abba Ammonas
GOD HEARS THE PRAYERS OF THE RIGHTEOUS
I write to you as men who love God, and seek Him with all your heart. For God will listen to such men when they pray, and will bless them in all things, and will grant them all the requests of their soul when they entreat Him. But those who come to Him not with their whole heart, but in two minds, who perform their works so as to be glorified by men -- such men will not be listened to by God in anything that they ask Him, but rather He is angry at their works. For it is written, "God has scattered the bones of the man-pleasers." (Psalms 53:5)
WORK TO PLEASE GOD, NOT TO PLEASE MEN
You see, then, how God is angry at the works of these men, and gives them none of the requests that they ask of Him, but rather resists them. For they do not their works in faith, but superficially. Therefore, the divine power does not dwell in them, but they are diseased in all their works, in whatever they set their hand to. For this reason they have not known the power of grace, nor its freedom from care, not its joy, but their soul is weighed down with a load in all their works. The greater part of our generation are such: they have not received the divine power that fattens the soul, prepares it to rejoice, and brings it day by day that gladness which makes the heart fervent in God. For the work that they do, they do as if it were for men. This is why this power does not come upon them; for an abomination to the power of God is the man who does his works as though for men's benefit.
FIGHT AGAINST PRIDE ABOVE ALL ELSE
Do you therefore, my beloved, whose fruit is reckoned in God, strive in all your works against the spirit of vainglory, that you may conquer it in all things, and that your whole body may be acceptable, and abide living with its Creator, and that you may receive the divine power, which is better than all these things. For I am persuaded, my beloved, that as long as you do all that is in your power in making war on the spirit of vainglory, and strive against it continually, your body will be alive. For this evil spirit attacks man in every work of righteousness to which he sets his hand, wanting to render his fruit useless and destroy it, thus preventing, as far as possible, men from performing works of righteousness; it wrestles with those who want to become faithful, and when any of them are praised by men for being faithful or humble or enduring shame, the evil spirit immediately engages in battle with them, and overcomes some of them, scattering and quenching their body. In so doing it prompts them to leave their virtuous way of life, and involve themselves in pleasing men, thus destroying their "body," though men reckon that they have gained something. This is why He does not give them the power, but leaves them empty, because He has not found their body good; and He deprives them of that great sweetness of grace.
But do you, my beloved, strive against the spirit of vainglory at all times, so that you may conquer it in everything, in order that the divine power may accompany you at all times. And I will pray God for you, that this joy may be given you always, for nothing is more free from care. And if after receiving this joy you see that your fervor withdraws and leaves you, seek it again and it will return. For this fervor is like fire which changes the cold into its own power. And if you see your heart weighed down temporarily, bring your soul before you and question it until it becomes fervent again and is set on fire in God. For the prophet David, too, on seeing his heart weighed down, said, "I have poured out my heart by myself (Psalms 42:4), I have remembered the days of old, and meditated on all your works, I lifted up my hands unto you; my soul thirsts after you as does a thirsty land." (Psalms 143:5-6) This is what David did when he saw his soul grow cold, until he had made it fervent again; and he received the divine sweetness both by day and by night. Do this, then, my beloved, and you will grow, and God will reveal to you great mysteries.
May God keep you in health of spirit and soul and body, till He brings you into the kingdom with your fathers who completed a good life, unto ages of ages, amen.
From Derwas J. Chitty (trans), "The Letters of Ammonas," (Oxford: SLG Press, Convent of the Incarnation, 1979), pp. 3 - 5