The Torah reading's last words make Amalek the eternal enemy of Israel, proclaiming "war with Amalek from generation to generation."
"When Moses held up his hand, Israel prevailed; when he let down his hand, Amalek prevailed. And the hands of Moses became heavy…" With these words the battle is decided; not just Moses' struggle, but the war of the generations, ours as well.
A Judaism of words alone has the weight of the air it isIsrael's perpetuation, its victory over the irresistible currents of history, is assured not by eloquence and noble ideals, but by its actions. The hands of Moses decide the battle. There are few abstract ideals, though Jewish in origin, that are not now part of the universal heritage of the civilized world. In the abstract, love of G‑d and mankind, the superiority of spirit over materialism, faith in the Creator -- these are not by themselves marks of Judaism or Jewishness. Other religions (and to a degree, non-religious people as well) profess these ideals.
The distinguishing characteristic of Israel is its concretization of these abstractions, its unique method of sanctifying human life and activities, its individual and exacting road to G‑dliness, and its own conception of the G‑dly life -- these make Judaism. Not the eloquence of oratory, not the profundities of theology, not the inspiration of the heart, but the tangible, physical hands, the deeds, the day-by-day affirmation by doing what G‑d demands of us -- these spell the victory of Israel over Amalek. When Jews "let down the hands,” when observance of Torah is neglected, then Amalek prevails, the future of Israel is in doubt. The Jew without mitzvot has little to make or keep him Jewish.
Of course Moses' hands are heavy -- performance of mitzvot, practicing self-control, bringing Judaism into every sphere of life -- this is no shortcut to Heaven. But there can be no viable, inspiring, worthwhile Judaism without mitzvot. A Judaism of words alone has the weight of the air it is. A Judaism of deeds, of mitzvot, has the solidity to survive the crush of persecution and the blandishments of assimilation, to prevail over any weapon the enemies of Israel can devise.