"'"But I will spare some, for some of you will escape the sword when you are scattered among the lands and nations."'" NIV translation
The principle of the remnant of God's people flows throughout the Bible and, here, it is promised again. God has always had a small group of people that, though they strayed, would always return to Him. The same thing is promised in this judgment on the northern kingdom.
"'"Then in the nations where they have been carried captive, those who escape will remember me - how I have been grieved by their adulterous hearts, which have turned away from me, and by their eyes, which have lusted after their idols. They will loathe themselves for the evil they have done and for all their detestable practices."'" NIV translation
This remnant of God's people all share the characteristic of a repentant heart. Though they may have faced a partial judgment by being exiled, they are yet saved from destruction. God's partial judgment was enough to get them to see their sin and to repent.
This is also the basis for the great revival that will take place during the time of the Great Tribulation. Many people will face a partial judgment of God in order for them to turn to Him.
"'"And they will know that I am the Lord; I did not threaten in vain to bring this calamity on them."'" NIV translation
The people will see that their idols were really nothing and that God is in control of all things. The people will also see that God knew that it was necessary for them to face the partial judgment in order to bring them back to Him. In the same manner, God knows that, in the last days, men's hearts will become so hard that the only way for them to come to Him is through severe judgments.
"'"This is what the Sovereign Lord says: Strike your hands together and stamp your feet and cry out 'Alas!' because of all the wicked and detestable practices of the people of Israel, for they will fall by the sword, famine and plague."'" NIV translation
Once again, God tells Ezekiel to act out a scene for the people. Striking the hands together and stomping the feet was a sign of great anguish. Saying alas was a sign that the judgment had been decreed and will not be stopped.