Are not two sparrows sold for a penny? Even hairs of your head are all numbered St. Jerome Commentary on Matt. 10: 29-31

 from St. Jerome Commentary on Matthew (Fathers of the Church transl. Vol. 117) published by CUA

2008 publication: Transl. by Thomas P. Scheck = Book 1 of Comm. 1:1 - 10:42) pages 123-4

Are not two sparrows sold for a penny? And not one of them falls to the ground without your Father.

But even the hairs of your head are numbered. Therefore, do not fear; you are worth more than many sparrows.

"The Lord's words are rooted in each other. What is said later depends upon what precedes.  

Prudent reader, always beware of a superstitious interpretation.

Do not accommodate the Scriptures to your meaning, but link your meaning

to the Scriptures and understand what follows.  Above he had said:

DO NOT FEAR THOSE WHO KILL THE BODY, BUT CANNOT KILL THE SOUL.

Now he speaks of the consequence of these words: ARE NOT TWO SPARROWS SOLD 

FOR A PENNY?

Thus the meaning:

If common and insignificant animals do not die apart from their Creator, God, 

and there is a providence in all things, and among these things 

the things that are going to perish do not perish without

the will of God, then you who are created should not fear that you live without the providence

of God (Footnote by Thomas Scheck: compare Origen, Fragment 211, 212). . .

Some force the passage about the two sparrows to refer to the soul and the body.

They also interpret as the senses the five sparrows (according to Luke (12:6) which are

sold for two pennies. . . If even insignificant animals do not die without the knowledge of God,

how much more man, who is supported with apostolic dignity?"