1. This chapter has two sections to it: first, there is the section dealing with complaint (again) and, second, there is the section dealing with the Amalekites. In one respect, it seems unfortunate that the chapter divisions are before us. In C-15 (15:22-27), C-16, and then in this first portion of C-17, we have one theme: complaint. Why the separation? In fact, as you look at each one of these sections, you’ll note that each section pertains to Israel’s movement toward Sinai (15:22-23; 16:1; 17:1).
2. The complaint. Once again there is no water for the people of Israel (17:1), and once again they complained against Moses (17:2). The people cried that the water was bitter (15:23), they had no food like they had in Egypt (16:3), and now they had no water (17:3). Moses makes plain their complaint was against the Lord, but this mattered not because the people were prepared to stone Moses (17:2, 4). Moses then takes his staff (another theme of the chapter) and strikes the rock at Horeb (some think this refers to a mountain range, in which Sinai was also located) and water comes out. From this rock comes water; another one of those miraculous occasions where the Lord provides. Whatever disappointment might have been felt in the people, the Lord does not address at this juncture.
3. The fight. Jews regard the Amalekites as the leading force of evil (Chumash, p. 391), and the reason they took this sneak attack, fight to the Israelites was because “Amalek wished to show its brazen denial of God and His power, and it was carrying on the ancient legacy of Esau’s hatred for Jacob” (ibid). Scholars, on the other hand, thinks that the reason for the attack was because Amalek felt threatened by Israel, though this is rejected by Jewish scholars. In any event, the Lord told Moses to tend to their threat. Moses does this by commissioning Joshua to head up the Israelite army and take the fight to Amalek. The Lord spoke against the Amalekites, declaring that their memory would be blotted out. “…the idea of removing the memory of a people is an idiom for destroying them — they will have no posterity and no lasting heritage” (NET, study note). With victory assured, Moses builds an altar to the Lord.
4. Application: Consider Moses’ charge against the Israelites; they were testing the Lord. Time and again the Lord miraculously demonstrated that He was providing for them. Time and again they lose sight of this and complain. Is it any wonder that as they were on the cusp of the promised land (Numbers 13 and 14) there was disbelief? That is why the Holy Spirit uses them as an example to us to not have a hardened heart (Hebrews 3 and 4).