O thou that hearest prayer - Who hast revealed thyself as a God hearing prayer - one of the leading characteristics of whose nature it is that thou dost hear prayer. Literally, "Hearer of prayer, to thee shall all flesh come." Nothing as applied even to God is more sublime and beautiful than the appellative "Hearer of prayer." Nothing in his attributes is of more interest and importance to man. Nothing more indicates his condescension and goodness; nothing so much encourages us in the endeavor to overcome our sins, to do good, to save our souls, and to save the souls of others. Dark and dismal would this world be, if God did not hear prayer; gloomy, inexpressibly gloomy, would be the prospects of man, if he had not the assurance that God is a prayer-hearing God - if he might not come to God at all times with the assurance that it is his very nature to hear prayer, and that his ear is ever open to the cries of the guilty, the suffering, the sad, the troubled, the dying.
Unto thee shall all flesh come - That is, all people - for the word is here used evidently to denote mankind. The idea is, that there is no other resource for man, no other help, no other refuge, but the God that hears prayer. No other being can meet his actual needs; and those needs are to be met only in connection with prayer. All people are permitted to come thus to God; all have need of his favor; all must perish unless, in answer to prayer, he interposes and saves the soul. It is also true that the period will arrive on earth when all flesh - all people - will come to God and worship him; when, instead of the scattered few who now approach him, all nations, all the dwellers on continents and islands, will worship him; will look to him in trouble; will acknowledge him as God; will supplicate his favor.

Unto thee shall all flesh come - All human beings should pray to God; and from him alone the sufficient portion of human spirits is to be derived. It is supposed to be a prediction of the calling of the Gentiles to the faith of the Gospel of Christ. A minister, immensely corpulent, began his address to God in the pulpit with these words: "O thou that hearest prayer, unto thee shall all flesh come!" and most unluckily laid a strong emphasis on All Flesh. The coincidence was ominous; and I need not say, the people were not edified, for the effect was ludicrous. I mention this fact, which fell under my own notice, to warn those who minister in righteousness to avoid expressions which may be capable, from a similar circumstance, of a ludicrous application. I have known many good men who, to their no small grief, have been encumbered with a preternatural load of muscles; an evil to be deprecated and deplored.

O thou that hearest prayer, unto thee shall all (b) flesh come.
(b) Not only the Jews but also the Gentiles in the kingdom of Christ.

O thou that hearest prayer,.... So as to answer it sooner or later, in one way or another, and always in the fittest time, and in the best way; so as to fulfil the requests and supply the wants of men, so far as may be for their good, and God's glory; which is a proof of the omnipresence, omniscience, and all sufficiency of God; who can hear the prayers of his people in all places at the same time, and knows all their persons and wants, and what is most proper for them, and can and does supply all their needs, and causes all grace to abound towards them; and it also shows his wondrous grace and condescension, to listen to the cries and regard the prayers of the poor and destitute;
unto thee shall all flesh come; being encouraged by the above character of him. All sorts of persons may come to him; men of all nations, of every rank and degree, condition and circumstance; there is no bar unto nor bounds about the throne of grace; the way to it lies open through the Mediator; and all sensible sinners shall and do come thither, though they are but "flesh", frail and mortal, corrupt and sinful creatures, and know themselves to be so; and they that come aright come through Christ, the new and living way, in his name, and in the faith of him, and of being heard for his sake, and under the gracious influences of the spirit of grace and supplication: it may be considered as a prophecy of the calling of the Gentiles, and of their calling upon God through Christ, and of their coming to God in his house, which was to be, and is, an house of prayer to all people, Isaiah 56:7.

All are encouraged to pray by God's readiness to hear.