The Divine law does not prescribe the impossible. Yet it prescribes perfection according to Matthew 5:48, "Be you . . . perfect, as also your heavenly Father is perfect." Therefore seemingly one can be perfect in this life.
I answer that, ....the perfection of the Christian life consists in charity. Now perfection implies a certain universality because according to Phys. iii, 6, "the perfect is that which lacks nothing." Hence we may consider a threefold perfection.
One is absolute, and answers to a totality not only on the part of the lover, but also on the part of the object loved, so that God be loved as much as He is lovable. Such perfection as this is not possible to any creature, but is competent to God alone, in Whom good is wholly and essentially.
Another perfection answers to an absolute totality on the part of the lover, so that the affective faculty always actually tends to God as much as it possibly can; and such perfection as this is not possible so long as we are on the way, but we shall have it in heaven.
The third perfection answers to a totality neither on the part of the object served, nor on the part of the lover as regards his always actually tending to God, but on the part of the lover as regards the removal of obstacles to the movement of love towards God, ..... Such perfection as this can be had in this life, and in two ways.
First, by the removal from man's affections of all that is contrary to charity, such as mortal sin; and there can be no charity apart from this perfection, wherefore it is necessary for salvation.
Secondly, by the removal from man's affections not only of whatever is contrary to charity, but also of whatever hinders the mind's affections from tending wholly to God. Charity is possible apart from this perfection, for instance in those who are beginners and in those who are proficient.
St Ignatius sums it up this way in his Principle and Foundation
Man is created to praise, reverence, and serve God our Lord, and by this means to save his soul.
And the other things on the face of the earth are created for man and that they may help him in prosecuting the end for which he is created.
From this it follows that man is to use them as much as they help him on to his end, and ought to rid himself of them so far as they hinder him as to it.
For this it is necessary to make ourselves indifferent to all created things in all that is allowed to the choice of our free will and is not prohibited to it; so that, on our part, we want not health rather than sickness, riches rather than poverty, honor rather than dishonor, long rather than short life, and so in all the rest; desiring and choosing only what is most conducive for us to the end for which we are created.
Augustine says in On Man's Perfection in Righteousness:
Although even now every man who progresses, advancing ever with an upright purpose, departs from all sin, and becomes further removed from it as he approaches nearer to the fulness and perfection of the righteous state; because even concupiscence itself, which is sin dwelling in our flesh, never ceases to diminish in those who are making progress, although it still remains in their mortal members. It is one thing, therefore, to depart from all sin,— a process which is even now in operation,— and another thing to have departed from all sin, which shall happen in the state of future perfection. But still, even he who has departed already from evil, and is continuing to do so, must be allowed to be a doer of good.