The Cross of Christ is the source of all blessings, the cause of all graces
From a sermon by Leo the Great:
Our understanding, which is enlightened by the Spirit of truth, should receive with purity and freedom of heart the glory of the cross as it shines in heaven and on earth. It should see with inner vision the meaning of the Lord's words when he spoke of the imminence of his passion:
By One Death and Resurrection the World Was Saved
When mankind was estranged from him by disobedience, God our Savior made a plan for raising us from our fall and restoring us to friendship with himself.
CONTEMLATING THE LORD'S PASSION:
From a sermon by Leo the Great, 5th century
True reverence for the Lord's passion means fixing the eyes of our heart on Jesus crucified and recognizing in him our own humanity. The earth - our earthly nature - should tremble at the suffering of its Redeemer.
The Body of Christ Gives Life to Those Who Receive It
From a Commentary on the Gospel of John by Cyril of Alexandria (376-444)
"I am dying for all men", says the Lord. "I am dying to give them life through myself and to redeem the whole human race through my humanity. In my death, death itself will die and man's fallen nature will rise again with me.