Christ came to bring us the help which only he could give. In his divinity he was immune to suffering; consequently, once he had assumed our fragile humanity, death could have no permanent hold on him. His immortal nature possessed the power to raise his dead body to life again.
We must cleave to this mystery always, striving with supreme effort of mind and body to be conformed to it. Although failure to observe the pascal solemnity would be very grave offense, it would be still more dangerous to take part in the liturgy without sharing in our Lord's passion. The Apostle's saying is true: If we suffer with him, we shall also reign with him.
We can give authentic worship to the suffering, dead, and risen Christ only if we ourselves suffer, die, and rise again with him. This sharing in Christ's Death and Resurrection begins for all the children of the Church at Baptism, in which sin is destroyed and thy are born to new life, the triple immersion in the water representing the Lord's three days sojourn in the grave. Their funeral pile, so to speak, is brought tumbling down, they enter the font in their old, sin-stained condition, to be brought forth new by the baptismal waters.
What has been effected sacramentally, however, must still be carried out in their daily lives. As long as thy are in this mortal body, those who are born of the Spirit must take up their cross.
So then, if anyone feels himself overstepping the bounds of Christian discipline and his desires drawing him away from the straight path, let him take refuge in the Lord's cross and nail his sinful passions to the tree of life. Let him cry to the Lord in the prophet's words: Pierce my flesh with the nails of your fear, I tremble at your judgements.
To pierce one's flesh with the nail of God's fear is to let the dread of divine judgment curb one's senses from unlawful desires. The person who thus resists temptation and mortifies his concupiscence to prevent it leading him into deadly sin will then be free to say with the Apostle: Far be it from me to boast of anything except the cross of Jesus Christ, through whom the world is crucified to me, and I the world.
Christ has lifted us up with himself on the cross; there let Christians take their stand. They know it is the place where their human nature was redeemed, and all their steps should be directed toward it. For the Lord's passion is prolonged until the end of the world. Just as it is he whom we honour and love in the saints, he whom we feed and clothe in the poor, so too is is he who suffers in all who endure adversity for the sake of what is right; unless, indeed, we are to imagine that, now that the faith has spread thorough out the world and the number of unbelievers has decreased, all persecution has come to an end together with every conflict which ever raged against the blessed martyrs- as if the bearing of the cross were reserved only for those who had to suffer atrocious torments for the love of Christ.
And so those wise souls who have learned to fear and love the one and only Lord and to hope in him alone mortify their passions and crucify their bodily senses, refusing either to fear their foes or to serve them. They prefer the will of God to their own lives, and insofar as they renounce love of self for love of God they love themselves all the more truly.
By such members of Christ's body as these the holy feast of Easter is authentically celebrated, and they will lack none of those victories which our Saviour's passion has won.
-- St Leo the Great (circa 400-461) was elected pope in 440. One hundred and forty-three of his letters and 96 sermons have survived.