"Hearken, O God, to my supplication, give heed to my prayer" [Psalm 61:1]. Who says? He, as if One. See whether one: "From the ends of the earth to You I have cried, while my heart was being vexed" [Psalm 61:2]. Now therefore not one: but for this reason one, because Christ is One, of whom all we are the members. For what one man cries from the ends of the earth? There cries not from the ends of the earth any but that inheritance, of which has been said to the Son Himself, "Demand of Me, and I will give to You the nations for Your inheritance, and for Your possession the boundaries of the earth." This therefore Christ's possession, this Christ's inheritance, this Christ's Body, this Christ's one Church, this the Unity which we are, is crying from the ends of the earth....But wherefore have I cried this thing? "While my heart was being vexed." He shows himself to be throughout all nations in the whole round world, in great glory, but in great tribulation. For our life in this sojourning cannot be without temptation: because our advance is made through our temptation, nor does a man become known to himself unless tempted, nor can he be crowned except he shall have conquered, nor can he conquer except he shall have striven, nor can he strive except he shall have experienced an enemy, and temptations. This Man therefore is being vexed, that from the ends of the earth is crying, but nevertheless He is not forsaken. For ourselves who are His Body He has willed to prefigure also in that His Body wherein already He has both died and has risen again, and into Heaven has ascended, in order that whither the Head has gone before, there the members may be assured that they shall follow. Therefore us He did transfer by a figure into Himself, when He willed to be tempted of Satan.
For that church is founded on a rock, as the Lord says: “On this rock I will build my church.” But they build on the sand, as the same Lord says: “Every one who hears these sayings of mine and does not do them is like a foolish man who built his house on the sand.” But that you may not suppose that the church that is on a rock is in only one part of the earth and does not extend even to its furthest boundaries, hear its voice groaning from the psalm, amid the evils of it pilgrimage. For it says, “From the end of the earth have I cried to you; when my heart was distressed you did lift me up on the rock; you have led me, you, my hope, have become a tower of courage from the face of the enemy.” See how it cries from the end of the earth.… See how it is exalted on a rock.
We should note that this flood of temptations assails the church in three ways: “one is tempted, drawn on and lured by one’s own desire,” or is worn down by the depravity of false brothers or is assaulted by the more open snares of those outside [the church]. In another place the Lord calls these temptations “the gates of the lower world,” and rightly so, for if victorious they drag us down to eternal destruction. He says, “I shall build my church on this rock, and the gates of the lower world shall not prevail against it.” Although the gates of the devil strike against it, yet they do not overthrow Christ’s church; although the flood of faithlessness inundates it, it does not undermine the house of faith. For [the church] is able to say truthfully to its helper, “When my heart was disquieted, you raised me up on a rock.” It is not vanquished by external forces because, by suffering and acquiring the crown of martyrdom, it triumphs over the ferocity of the unbelievers who persecute it. It is not corrupted by false brothers because it refutes the dogmas of heretics by believing properly, and it avoids the vicious example of some Catholics by living soberly and justly and piously. It is not blinded by the smoke of private greed because it is inwardly aflame with the ardor of the Lord’s charity alone.
[AD 430] Augustine of Hippo on Psalms 61:2