Lamb and Sheep

When they had finished breakfast, Jesus said to Simon Peter, "Simon, son of John, do you love me more than these?" He said to him, "Yes, Lord, you know that I love you." He said to him, "Feed my lambs." He then said to him a second time, "Simon, son of John, do you love me?" He said to him, "Yes, Lord, you know that I love you." He said to him, "Tend my sheep." He said to him the third time, "Simon, son of John, do you love me?" Peter was distressed that he had said to him a third time, "Do you love me?" and he said to him, "Lord, you know everything; you know that I love you." (Jesus) said to him, "Feed my sheep. Amen, amen, I say to you, when you were younger, you used to dress yourself and go where you wanted; but when you grow old, you will stretch out your hands, and someone else will dress you and lead you where you do not want to go." He said this signifying by what kind of death he would glorify God. And when he had said this, he said to him, "Follow me."

Feed my lambs

Tend my Sheep

Feed my Sheep

I just noted the following:

Lambs, plural; Sheep, singular;

Lambs are younger sheeps, and Peter has to feed them, maybe Jesus is refering to newly baptised Christians. But why Jesus told peter to tend and feed his sheep in singular form. Who could this be?