From the context we learn that it is "of the Lord's mercies" that we are not consumed. And it is also because of the fact that His compassions toward us do not fail. The writer then asserts that these compassions are "new every morning,"---after which he reminds us of the greatness of God's faithfulness. 

    In Psalm 39 David expressed the desire that the Lord would so deal with him that he might know how frail he was. One of the most remarkable faults of fallen men is their ignorance of their innate frailty and weakness. They may not agree that they are their "brother's keeper" but they at least act as though they think they are their own keeper. Little do they realize how utterly dependent they are on the mercy of God to preserve their lives, to say nothing of keeping them from the myriad dangers each of us face daily. 

    We sometimes come to the close of day feeling that almost everything is drained out of us. At such times we may feel little ambition to even try to go on. We may feel greatly discouraged, distraught and downcast, and yet, after a night's rest we often find that the picture looks quite different; we feel a renewed strength and fresh resolve and determination; our faith seems stronger and our hope seems brighter. This is because God's compassions are indeed "new every morning" and they do not fail. 

    Paul says that though our outward man perish, yet the inward man is renewed day by day (See II Cor. 4:16). God does not give us tomorrow's strength today. We do not need tomorrow's strength today. We only need today's strength, and the Lord knows how much that is, or is going to be. We are to pray for our daily bread, not tomorrow's bread. "This is the day which the lord hath made" (See Psalm 118:24), and it is this day that we are to be primarily concerned with. For all we know God may not make another day, so let us rejoice and be glad in this one.