“Be you therefore perfect, as also your heavenly Father is perfect.” (Matt. 5:48)
“Be ye holy, because I the Lord your God am holy.” (Lev. 19:2)
Having just concluded studying St. John’s gospel stating that Jesus showed how perfect his love was. “having loved his own who were in the world, he loved them unto the end.” (Jn.13:1) What does this mean? Of course, we know that Jesus was/is perfect. After all, he is God. Yes, he was man, too, but he had an edge as God and man. “Be holy as God is holy.” These words have often haunted me. I have resisted and rejected them as impossible. Minimised them by saying human beings are of their very nature finite, limited, sinners. How can we be perfect? Then I remember St. Paul’s words which always amaze me. “Him, who knew no sin, he hath made sin for us, that we might be made the justice of God in him.” (2 Cor. 5:21)
Whenever we enter into the events of the last days in Jesus’ life, we confront most vividly this mystery of God’s perfection and holiness. Jesus gives us an example of what holiness demands to the point of death. Even Jesus’ act of washing his apostles’ feet that we ritually perform now contains all the wonder and depth of God’s love as it is in itself and as it is manifested toward us. Is it possible that we can live this same holiness, this same goodness and love to perfection as Jesus does?
While in the library recently I came across an article by the Servant of God, theologian, author and physician Adrienne von Speyr (1902 – † 1967) entitled, “Holiness in the Everyday.” This is a favourite theme of mine, to be holy in our everyday life — nothing spectacular, just a responding to the ordinariness of life with no worries about having to be perfect. I started to read and realised to my surprise that she is speaking of the same issue I just brought up: the demand of Jesus that we be perfect as his heavenly Father. How do we do it? Quite simply… ‘by a leap of faith’. This might seem too easy but I don’t think so. However, I have jumped ahead some so let me explain as best I can.
I am sure you have had the experience of a tune going through your mind all day or have replayed in your mind some disturbing incident. It is as if our psyche has a life of its own as we go about our daily work. What if we were to stop and realise that this inner space or world is easily shaped by random happenings, for instance, a song we heard or an event that occurred? Would we wonder if we have the capacity to let this inner space be affected by something more substantial, by an abiding inner choice, by a source that is with us throughout the day enabling us to live a holy life? We should, because this inner space is designed first of all for the Word of God. The space, the inner world that we now keep for ourselves and allow to be filled by peripheral enjoyments or distractions is meant to be the place where God’s word lives, just as “God’s seed lived in Mary: growing and pervading everything.” We are called to be a bearer of that word, to let it live in us and be everything in us.
And what would be an example of this word we must bear? “Be perfect as your heavenly Father is perfect.” There is no minimising this call. There is no picking and choosing of which word we want to bear. We can not believe the easy sayings and gradually build up to the more difficult ones. As St. John says, we can’t call God a liar. If he demands it, it is possible. No…
Faith means risking, (taking) the whole at once, immediately receiving and affirming the most unbelievable, most impossible-to-translate words. (If you do this) you find yourself, all escape cut off, face-to-face with the Absolute, and, all escape cut off, (obliged) to surrender to this Absolute, this ‘impossibility,’ the room it demands…. It is the inmost place in me, the centre from which all the other points and spaces of my soul can be occupied and ordered. … In a word: (we are asked) to make room in ourselves for God in place of our self.
Who can make this demand of us but Jesus? His whole life was doing the Father’s will.
When he became man (he) took our everyday upon himself in order to fill it with the Father’s eternal day. Coming down from above (he) reached out of eternity and laid hold of temporality, in order to make it the vessel of eternal life, undiminished, undimmed, and uncompromising. This abasement preserves his whole divine dignity: he doesn’t compromise himself by it; even as man he is holy as God the Father is holy. His way of living of perfection keeps it open to us, too. Accomplishing the incredible, he invites us to perform it, although in the inverse direction. He invites us, that is, to cast ourselves up from below into this holiness, which, after all, is governed by the Father’s holiness, in order to embody it in accord with our personal character and mission.
This leap … is first and foremost an act of faith. 
We know we cannot be holy as God is holy. Yet we can believe that what Jesus asks of us is possible. There is no rational answer to all of this because it is an act of God in us if we will really let God do it. It is an act in which we must unconditionally stop relying on the criteria of what we can grasp and measure. As von Speyr says:
No believer will ever be able to see, understand, or assert his own holiness. On the other hand, his faith equally forbids him to assert that God can’t really do in him what he says. The believer leaves the clear vision, the comprehension, to God. 
I have to say that this brought about in me a whole different way of thinking about holiness and perfection. We all believe that the Blessed Trinity dwells in us through baptism. He is holy, he lives in me, so I am holy. Favourite quotes from St. Paul have taken on a deeper meaning. “And I live, now not I; but Christ liveth in me.” (Gal. 2:20) Paul doesn’t have two lives, his own and Christ’s — but one, Christ’s. Christ is holy; Christ is my life, so I am holy; yet, I cannot see it. It is God’s holiness. I am no longer trying for perfection by my own efforts. …but I want only the perfection that “may be found in him, not having my justice, which is of the law, but that which is of the faith of Christ Jesus, which is of God, justice in faith.” (Phil. 3:9) I, the believer, must leave to God the clear vision, the comprehension of this great mystery within me. Now the life you have is hidden with Christ in God. “When Christ shall appear, who is your life, then you also shall appear with him in glory.” (Col. 3:4)
Jesus gives us another of his words for us to bear and let live in us. “Then after he had washed their feet, and taken his garments, being set down again, he said to them: ‘Know you what I have done to you? You call me Master, and Lord; and you say well, for so I am. If then I being your Lord and Master, have washed your feet; you also ought to wash one another’s feet. For I have given you an example, that as I have done to you, so you do also..’” (Jn 13:12-15) In our everyday life we are given many opportunities to do this if we are open to letting go of our own life and desires and letting God live in us. For it is in living our ordinary life that we are being made perfect in God’s love and holiness.
St. Paul expressed it to his spiritual children in one of his most beautiful passages which I am taking from The Living Bible:
“When I think of the wisdom and scope of his plan,
I fall down on my knees and pray to the Father of all the great family of God —
some of them already in heaven and some down here on earth —
that out of his glorious, unlimited resources
he will give you the mighty inner strengthening of his Holy Spirit.
And I pray that Christ will be more and more at home in your hearts,
living within you as you trust in him.
May your roots go down deep into the soil of God’s marvellous love;
and may you be able to feel and understand, as all God’s children should,
how long, how wide, how deep, and how high his love really is;
and to experience this love for yourselves,
though it is so great that you will never see the end of it
or fully know or understand it.
And so at last you will be filled up with God himself.
Now glory be to God, who by his mighty power at work within us
is able to do far more than we would ever dare to ask or even dream of —
infinitely beyond our highest prayers, desires, thoughts, or hopes,
May he be given glory forever and ever through endless ages
because of his master plan of salvation for the Church through Jesus Christ.” 
Free Book Download (PDF)
 Author: Sr.. David Marie O.P. Woodstock (IL), ‘Is Perfection Possible?’ Dominican Monastic Search Vol. 20, 2002-03, pp. 53-56.
 Communio: International Catholic Review, Vol. XXIX, No. 4, (Winter 2002).
 Ibid., p. 753.
 Ibid., pp. 753-754.
 Ibid., p. 754.
 Ibid., pp. 754-755.
 The Living Bible (1971) by Tyndale House Foundation.