I. The mystery of the Passion passes man's comprehension
The Feast of the Lord's Passion that we have longed for and that the whole world may well desire, has come, and suffers us not to keep silence in the tumult of our spiritual joys: because though it is difficult to speak often on the same thing worthily and appropriately, yet the priest is not free to withhold from the people's ears instruction by sermon on this great mystery of God's mercy, inasmuch as the subject itself, being unspeakable, gives him ease of utterance, and what is said cannot altogether fail where what is said can never be enough.
Let human frailty, then, succumb to God's glory, and ever acknowledge itself unequal to the unfolding of His works of mercy. Let us toil in thought, fail in insight, falter in utterance: it is good that even our right thoughts about the Lord's Majesty should be insufficient. For, remembering what the prophet says, “Seek the Lord and be strengthened: seek His face always,” no one must assume that he has found all he seeks, lest he fail of coming near, if he cease his endeavours.
And amidst all the works of God which weary out man's wondering contemplation, what so delights and so baffles our mind's gaze as the Saviour's Passion? Ponder as we may upon His omnipotence, which is of one and equal substance with the Father, the humility in God is more stupendous than the power, and it is harder to grasp the complete emptying of the Divine Majesty than the infinite uplifting of the “slave's form” in Him. But we are much aided in our understanding of it by the remembrance that though the Creator and the creature, the Inviolable God and the passible flesh, are absolutely different, yet the properties of both substances meet together in Christ's one Person in such a way that alike in His acts of weakness and of power the degradation belongs to the same Person as the glory.
Source: Sermons (New Advent)