Albert Barnes on Matthew 10:29-31

Are not two sparrows, etc. He encourages them not to fear by two striking considerations: first, that God took care of sparrows, the smallest and least valuable birds; and, secondly, by the fact, that God numbered even the very hairs of the head. The argument is, if he takes care of birds of the least value; if he regards so small a thing as the hair of the head, and numbers it, he will certainly protect and provide for you. You need not, therefore, fear what man can do to you.

Sparrows. Birds of very small kind and value, with a black throat, and brown temples. They were used for food among the Jews; and were an image of sorrow, solitude, and wretchedness. Ps 102:7. "I am as a sparrow alone upon the house top."

Farthing. Mt 5:26.

Without your Father. That is, God your Father guides and directs its fall. It falls only with his permission, and where he chooses.

(1) "farthing" "halfpenny farthing, a 10th part of the Roman penny" Mt 18:28