28 Christ is the end of the law; but, tell me, is He come to destroy it or to fulfil it? And if Christ, the end of the law, does not destroy it, but fulfils it (as He says, I have come not to destroy the law but fulfil it), is not the end of the law, so far from being its dissolution, the very opposite, namely its final perfection? All things are advancing towards an end, but that end is a condition of rest in the perfection, which is the goal of their advance, and not their abolition.
Further, all things exist for the sake of the end, but the end itself is not the means to anything beyond: it is an ultimate, all-embracing whole, which rests in itself. And because it is self-contained, and works for no other time or object than itself, the goal is always that to which our hopes are directed. Therefore the Lord exhorts us to wait with patient and reverent faith until the end comes: Blessed is He that endures to the end. It is not a blessed dissolution, which awaits us, nor is non-existence the fruit, and annihilation the appointed reward of faith: but the end is the final attainment of the promised blessedness, and they are blessed who endure until the goal of perfect happiness is reached, when the expectation of faithful hope has no object beyond.
Their end is to abide with unbroken rest in that condition, towards which they are pressing. Similarly, as a deterrent, the Apostle warns us of the end of the wicked, Whose end is perdition,..... but our expectation is in heaven. Suppose then we interpret the end as a dissolution, we are forced to acknowledge that, since there is an end for the blessed and for the wicked, the issue levels the godly with the ungodly, for the appointed end of both is a common annihilation.
What of our expectation in heaven, if for us as well as for the wicked the end is a cessation of being? But even if there remains for the saints an expectation, whereas for the wicked there waits the end they have deserved, we cannot conceive that end as a final dissolution. What punishment would it be for the wicked to be beyond the feeling of avenging torments, because the capability of suffering has been removed by dissolution? The end is, therefore, a culminating and irrevocable condition which awaits us, reserved for the blessed and prepared for the wicked.
Source: On the Trinity (New Advent)