Church Fathers on Luke 10:4

Luke next relates, that the seventy disciples obtained for themselves from Christ apostolical learning, lowliness, innocency, justice, and to prefer no worldly things to holy preachings, but to aspire to such fortitude of mind as to be afraid of no terrors, not even death itself. He adds therefore, Go.

For their comfort amid every danger was the power of Him who sent them. And therefore said He, Behold, I send you; as if he said, This will suffice for your consolation, this will be enough to make you hope, instead of fearing the coming evils which He signifies, adding, as lambs among wolves.

Denoting the simplicity and innocence in His disciples. For those who were riotous, and by their enormities did despite to their nature, He calls not lambs, but goats.