Gregory of Nyssa

But when the shepherd had found the sheep, he did not punish it, he did not get it to the flock by driving it, but by placing it upon his shoulder, and carrying it gently, he united it to his flock. Hence it follows, And when he hath found it, he layeth it upon his shoulders rejoicing.

Catena Aurea by Aquinas ↗

Theophylact of Ohrid

The Lord, having found this lost sheep, laid it on His shoulders. For "He bore our infirmities" and sins (Isa. 53:4), and without being burdened He took upon Himself all our loads; He paid all that we owed, and easily and without labor He saved us and brought us to His very home, that is, to heaven.

Commentary on Luke ↗

Ambrose of Milan

Let us rejoice that the sheep that had strayed in Adam is lifted on Christ. The shoulders of Christ are the arms of the cross. There, I laid down my sins. I rested on the neck of that noble yoke. The sheep is one in kind, not in appearance, because "we are all one body" but many members. It is written, "You are the body of Christ, and members individually." "The Son of man came to seek and save what was lost." He sought all, because "as in Adam all men die, so also in Christ shall all be made alive."

Exposition of the Gospel of Luke ↗

Gregory the Dialogist

And when he finds the sheep, he lays it on his shoulders rejoicing. He placed the sheep on his shoulders because by taking on human nature he himself bore our sins.

Forty Gospel Homilies, Homily 34 ↗

Bede

And when he has found it, he lays it on his shoulders, rejoicing. He laid the sheep on his shoulders because, taking on human nature, He Himself bore our sins.

On the Gospel of Luke ↗