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.
Pope Leo IA 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.
Pope Leo ILet 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.
Pope Leo I... 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.
Pope Leo I