The loving kindness of the Lord is manifested when his long-suffering is shown in the fact that he does not immediately destroy all such, but gives each one a full and fair opportunity, the Prophet showing that each one shall have at least a hundred years of trial; and if at the end of that time he is persistent in disobeying the Lord, he shall be counted accursed and cut off in everlasting destruction.

(Isaiah 65:20) St.Peter corroborated this in his statement concerning restoration times, saying: "It shall come to pass, that every soul, which will not hear that prophet, shall be destroyed from among the people" .-- Acts 3:23.
[572]Again the testimony of Jesus is to the effect that at the beginning of his reign the nations and peoples shall be gathered before him in the sense that they will be instructed concerning his reign.

In parabolic phrase he pictures them being separated as sheep are separated from goats.

A goat is an animal that is unruly, disobedient.

It refuses to stay in the pasture where it is placed, but insists on getting outside and destroying things where it has no business.