Zachor: What Does It Matter That They Were Faint and Weary?

From the end of parshat Ki Teitzei:

יז זָכוֹר, אֵת אֲשֶׁר-עָשָׂה לְךָ עֲמָלֵק, בַּדֶּרֶךְ, בְּצֵאתְכֶם מִמִּצְרָיִם.	17 Remember what Amalek did unto thee by the way as ye came forth out of Egypt;
יח אֲשֶׁר קָרְךָ בַּדֶּרֶךְ, וַיְזַנֵּב בְּךָ כָּל-הַנֶּחֱשָׁלִים אַחֲרֶיךָ--וְאַתָּה, עָיֵף וְיָגֵעַ; וְלֹא יָרֵא, אֱלֹהִים.	18 how he met thee by the way, and smote the hindmost of thee, all that were enfeebled in thy rear, when thou wast faint and weary; and he feared not God.
יט וְהָיָה בְּהָנִיחַ ה אֱלֹהֶיךָ לְךָ מִכָּל-אֹיְבֶיךָ מִסָּבִיב, בָּאָרֶץ אֲשֶׁר ה-אֱלֹהֶיךָ נֹתֵן לְךָ נַחֲלָה לְרִשְׁתָּהּ--תִּמְחֶה אֶת-זֵכֶר עֲמָלֵק, מִתַּחַת הַשָּׁמָיִם; לֹא, תִּשְׁכָּח. {פ}	19 Therefore it shall be, when the LORD thy God hath given thee rest from all thine enemies round about, in the land which the LORD thy God giveth thee for an inheritance to possess it, that thou shalt blot out the remembrance of Amalek from under heaven; thou shalt not forget. {P}

Why the stress on וְאַתָּה עָיֵף וְיָגֵעַ? Perhaps to stress Amalek's treachery. Indeed, some commentators make something out of this theme. For an example, I just saw, Shadal connects the treachery of the woman grabbing the man's mevushav, which he did not expect and was thus unfair, with trickery in the even vaaven, and finally with Amalek, as a reason for finishing them off.

I would suggest that there is a different theme at play here, either in place of the other, or as an addition. Namely, at the time, the Israelites were not able to stand up for themselves, for their own honor, and for the honor of Hashem. Why? Because at that time they were "faint and weary." But once they get settled -- בְּהָנִיחַ ה אֱלֹהֶיךָ לְךָ מִכָּל-אֹיְבֶיךָ מִסָּבִיב, בָּאָרֶץ אֲשֶׁר ה-אֱלֹהֶיךָ נֹתֵן לְךָ נַחֲלָה לְרִשְׁתָּהּ -- then, they are to turn around and settle the score with Amalek. I think the contrast between the two pesukim is deliberate.