Saul came to a city of Amalek - I believe the original should be translated, and Saul came to the city Amalek; their capital being called by the name of their tribe.

And Saul came to a city of Amalek,.... With his army, perhaps the nearest city of it to the land of Israel; though some think that Amalek was the name of the city, and was the metropolis of the nation, and had its name from thence: and laid wait in the valley; which was near the city, to intercept the inhabitants when they should come out against him: or "he contended" (w) as some render it, he fought with them there; the Targum,"he ordered his army,''set them in battle array, or pitched his camp there.

(w) "et certavit Pagninus"; "ut contenderet cum eo", Junius & Tremellius.

He then advanced as far as the city of the Amalekites, the situation of which is altogether unknown, and placed an ambush in the valley. ויּרב does not come from ריב, to fight, i.e., to quarrel, not to give battle, but was understood even by the early translators as a contracted form of ויּארב, the Hiphil of ארב. And modern commentators have generally understood it in the same way; but Olshausen (Hebr. Gramm. p. 572) questions the correctness of the reading, and Thenius proposes to alter בּנּחל ויּרב into מלחמה ויּערך. נחל refers to a valley in the neighbourhood of the city of the Amalekites.

And Saul came to a city of Amalek, and laid wait in the valley.

laid...: or, fought

5. Saul came to a city of Amalek-probably their capital.

laid wait in the valley-following the strategic policy of Joshua at Ai (Jos 8:4).

15:1-9 The sentence of condemnation against the Amalekites had gone forth long before, Ex 17:14; De 25:19, but they had been spared till they filled up the measure of their sins. We are sure that the righteous Lord does no injustice to any. The remembering the kindness of the ancestors of the Kenites, in favour to them, at the time God was punishing the injuries done by the ancestors of the Amalekites, tended to clear the righteousness of God in this dispensation. It is dangerous to be found in the company of God's enemies, and it is our duty and interest to come out from among them, lest we share in their sins and plagues, Re 18:4. As the commandment had been express, and a test of Saul's obedience, his conduct evidently was the effect of a proud, rebellious spirit. He destroyed only the refuse, that was good for little. That which was now destroyed was sacrificed to the justice of God.