Pope Leo I quotes:

The Child, the Lord Jesus Christ . . . Word in our flesh, Wisdom in infancy, Power in weakness, and in true Man, the Lord of Majesty.

The cross of Christ is the true ground and chief cause of Christian hope.

Beyond our grasp, He chose to come within our grasp. Existing before time began, He began to exist at a moment in time.

By Baptism we are made flesh of the Crucified

And each one is a partaker of this spiritual origin in regeneration; and to every one when he is re-born, the water of baptism is like the Virgin's womb; for the same Holy Spirit fills the font, Who filled the Virgin, that the sin, which that sacred conception overthrew, may be taken away by this mystical washing.

The faith by which we live shall never vary in any age . . . for one is the faith which sanctifies the Just of all ages.

A true worshipper is one whose mind has not been defiled with any false belief.

I have neither permitted, nor shall I permit, the things which have been settled by the holy fathers to be violated by any innovation.

Each needs the other: capital cannot do without labor, nor labor without capital.

Peace is the first thing the angels sang. Peace is the mark of the children of God. Peace is the nurse of love. Peace is the mother of unity. Peace is the rest of the blessed souls. Peace is the dwelling place of eternity.

The birthday of the Lord is the birthday of peace.

The Church is a virgin, the bride of one Spouse, Who is Christ, and this Church does not allow herself to be violated by any error; so that, throughout the whole world there may be for us one uncorruptedness of a single chaste communion.

Truth, which is simple and one, admits of no variety.

... the Apostle says, 'he that says he abides in Christ ought himself also to walk as He walked' (I Jn. 2:6). Otherwise we make a vain pretence and show, if we follow not His steps, Whose name we glory in, and assuredly they would not be irksome to us, but would free us from all dangers, if we loved nothing but what He commanded us to love.

As the world attracts us with its appearance, and abundance and variety, it is not easy to turn away from it unless in the beauty of things visible the Creator rather than the creature is loved; for, when He says, 'you shall love the Lord your God from all your heart, and from all your mind, and from all your strength' (Mt. 22:37), He wishes us in nothing to loosen ourselves from the bonds of His love. And when He links the love of our neighbor also to this command, He enjoins on us the imitation of His own goodness, that we should love what He loves and do what He does.

It is not enough to know the Son of God in the Father's nature only, unless we acknowledge Him in what is ours without withdrawal of what is His own. For that self-emptying, which He underwent for man's restoration, was the dispensation of compassion, not the loss of power. For, though by the eternal purpose of God there was 'no other name under heaven given to men whereby they must be saved' (Acts 4:12), the Invisible made His substance visible, the Intemporal temporal, the Impassable passable: not that power might sink into weakness, but that weakness might pass into indestructible power.

A great safeguard is the entire faith, the true faith, in which neither anything whatever can be added by anyone nor anything taken away; for, unless faith be one, it is not the faith.

David's Lord was made David's Son, and from the fruit of the promised branch sprang One without fault, the two-fold nature coming together in one Person, that by one and the same conception and birth might spring our Lord Jesus Christ, in Whom was present both true Godhead for the performance of mighty works and true Manhood for the endurance of sufferings.

God ordained for every man one and the same means of salvation.

He that sees another in error and endeavors not to correct it, testifies himself to be in error.

Let no one be ashamed of the cross by which Christ has redeemed the world. None of us must be afraid to suffer for the sake of justice or doubt the fulfillment of the promises, for it is through toil that we come to rest and through death that we pass to life.

No one, however weak, is denied a share in the victory of the cross. No one is beyond the help of the prayer of Christ.

Teach nothing new, but instill into all men's breasts those things which the Fathers of revered memory have with harmony of statement taught... Preach nothing else than what we received from our forefathers... Accordingly, both in the rule of faith and in the observance of discipline, let the standard of antiquity be maintained throughout.

The devil is always discovering something novel against the truth.

The faith of those who live their faith is a serene faith. What you long for will be given you; what you love will be yours for ever.

The faith of those who live their faith is a serene faith. What you long for will be given you; what you love will be yours for ever. Since it is by giving alms that everything is pure for you, you will also receive that blessing which is promised next by the Lord: the Godhead that no man has been able to see. In the inexpressible joy of this eternal vision, human nature will possess what eye has not seen or ear heard, what man's heart has never conceived.

Those who are not good to others are bad to themselves.

Virtue is nothing without the trial of temptation, for there is no conflict without an enemy, no victory without strife.