Cyril of Alexandria

The Scribes and Pharisees who had become spectators of Christ's miracles, heard Him also teaching. Hence it is said, And it came to pass on a certain day, as he was teaching, that there were Pharisees sitting by, &c. And the power of the Lord was present to heal them. Not as though He borrowed the power of another, but as God and the Lord He healed by His own inherent power. Now men often become worthy of spiritual gifts, but generally depart from the rule which the giver of the gifts knew. …

Catena Aurea by Aquinas ↗

Bede

And it happened on one of the days, and he was sitting teaching, and there were Pharisees sitting, etc. Where the Lord, sitting and teaching, cured the paralytic when the scribes and Pharisees were sitting, Luke omits for brevity's sake, but Matthew and Mark, who narrate it, seem to question it. Since indeed Matthew testifies that he did this in his own city, and Mark in Capernaum. Which would be more difficult to resolve if Matthew also named Nazareth. …

On the Gospel of Luke ↗

Bonaventure

And it came to pass on one of the days. Having confirmed the disciples through the healing of the leper, here for greater firmness he confirms the same through the wondrous healing of the paralytic. The Evangelist describes this admirable healing in the following order. For first is introduced the opportunity for performing the miracle: second, the completeness of the miracle accomplished, at: Whose faith etc.: third, the renown of the miracle made public, at: And astonishment seized etc. …

Commentary on Luke, Chapter 5 ↗