What will be "b'Kerev ha'Aretz b'Soch ha'Amim"?
Rashi: Yisrael will remain among the nations - "Echad me'Ir u'Shenayim mi'Mishpachah" (Yirmeyah 3:14).
Radak: Everything mentioned, until those remaining will be "k'Nokef Zayis k'Olelos..."
What is "k'Nokef Zayis"?
Rashi: He leaves individual olives on the treetop.
Radak: When one bangs an olive-tree, a small number of olives do not fall from one bang - one here and one there.
Malbim: At that time Yisrael will be in Eretz Yisrael "k'Nokef Zayis" - he takes all the fruits, one at a time. So they will kill and exile all of them.
What are "k'Olelos Im Kalah Vatzir"?
Radak: After one harvests his vineyard, a small number of Olelos (deficient clusters) remain. So will be the nations, for most of them will perish. The few who remain will admit to Kel and His ability, that He is Master of everything, when they see the fall of Gog and Magog. It says about them "Likro Chulam b'Shem Hashem Le'avdo Shechem Echad" (Tzefanyah 3:9). Similarly, those who remained from Machaneh Ashur, when they saw its fall, returned to serve Hashem, like I explained above (refer to 19:18:1:1 and the note there). Im Kalah is like Ka'asher Kalah. The same applies to "v'Im Yihyeh ha'Yovel" (Bamidbar 36:4), "Im Mizbe'ach Avanim Ta'aseh Li" (Shemos 20:23) and similar verses.
Malbim: Amidst the nations, in Chalach and Chavor 1 Yisrael will be few, like Olelos that remain after the grape harvest.
To which Sancheriv exiled the 10 tribes (Melachim II, 17:6).