Albert Barnes Commentary Luke 1:66

"And all that heard them laid them up in their heart, saying, What then shall this child be? For the hand of the Lord was with him." — Luke 1:66 (ASV)

What manner of child, and so on. Such were the remarkable circumstances of his birth that they understood that he would be distinguished as a prophet, or that great events would result from his life.

The hand of the Lord was with him. The word hand is used to denote aid, protection, favour. We stretch out the hand to aid those whom we wish to help. The expression here means that God aided him, protected him, or showed him favour. Some think that these words are a part of the speech of the neighbours—"What manner of child shall this be? God is so evidently with him!"