What does it mean to be perfect? Perfect is defined as that which is complete or whole. So a perfect house, or a perfect car, is one that is complete—it has everything it needs to function well, as a house or as a car. The imperfect is anything that lacks wholeness and completeness. So a house without a roof is imperfect, and a car with no motor is imperfect.
My reason for raising this subject is that Our Lord tells us, in Matthew 5:48, that we should be perfect as our heavenly Father is perfect. Also, I have noticed, in reading St. Thomas Aquinas, that he often uses the distinction between what is imperfect and what is perfect.
Our ultimate goal in life, a supernatural goal, which is the face-to-face vision of God in heaven for all eternity, is a state of perfection. Everyone in heaven right now is perfect. Each one is perfect, according to the degree of grace attained, according to divine providence, something similar to the hierarchies of angels. God alone is infinitely perfect in every way.
Perfection in this life means developing all of one’s faculties, and practicing all the virtues, especially the theological virtues of faith, hope and charity, and the moral virtues of prudence, justice, fortitude and temperance. For example, what is required by the Church in the canonization process is that the individual under consideration must be proven to have practiced heroic virtue, that is, to have achieved a certain perfection...
Is perfection attainable for weak human beings? The answer is:“Yes!” but only with the grace of God, universal charity, the practice of the Beatitudes, and letting the Holy Spirit work in us through his Seven Gifts. As the Christian striving for perfection gets closer to the goal, he or she is filled with love for God and man, radiating the joy which is manifested in the Twelve Fruits of the Holy Spirit. We are all called to strive for perfection. Therefore, it is important to pray every day for the grace to achieve it. There is nothing in this life more important than attaining perfection in imitation of Christ Our Lord.
(Fr. Kenneth Baker, On striving for perfection)