They sung. Hebrew, “sing ye unto it,” in chorus, men and women. Septuagint, “commence a canticle unto it. This well the princes dug, the kings of nations hewed in the rock, in their kingdom, while they held dominion.”

Matthew Henry Commentary on the Whole Bible (Complete) (Matthew Henry)

21 And Israel sent messengers unto Sihon king of the Amorites, saying, 22 Let me pass through thy land: we will not turn into the fields, or into the vineyards; we will not drink of the waters of the well: but we will go along by the king's high way, until we be past thy borders. 23 And Sihon would not suffer Israel to pass through his border: but Sihon gathered all his people together, and went out against Israel into the wilderness: and he came to Jahaz, and fought against Israel. 24 And Israel smote him with the edge of the sword, and possessed his land from Arnon unto Jabbok, even unto the children of Ammon: for the border of the children of Ammon was strong. 25 And Israel took all these cities: and Israel dwelt in all the cities of the Amorites, in Heshbon, and in all the villages thereof. 26 For Heshbon was the city of Sihon the king of the Amorites, who had fought against the former king of Moab, and taken all his land out of his hand, even unto Arnon. 27 Wherefore they that speak in proverbs say, Come into Heshbon, let the city of Sihon be built and prepared: 28 For there is a fire gone out of Heshbon, a flame from the city of Sihon: it hath consumed Ar of Moab, and the lords of the high places of Arnon. 29 Woe to thee, Moab! thou art undone, O people of Chemosh: he hath given his sons that escaped, and his daughters, into captivity unto Sihon king of the Amorites. 30 We have shot at them; Heshbon is perished even unto Dibon, and we have laid them waste even unto Nophah, which reacheth unto Medeba. 31 Thus Israel dwelt in the land of the Amorites. 32 And Moses sent to spy out Jaazer, and they took the villages thereof, and drove out the Amorites that were there. 33 And they turned and went up by the way of Bashan: and Og the king of Bashan went out against them, he, and all his people, to the battle at Edrei. 34 And the Lord said unto Moses, Fear him not: for I have delivered him into thy hand, and all his people, and his land; and thou shalt do to him as thou didst unto Sihon king of the Amorites, which dwelt at Heshbon. 35 So they smote him, and his sons, and all his people, until there was none left him alive: and they possessed his land.

Matthew Henry Commentary on the Whole Bible (Concise) (Matthew Henry)

Verses 10-20 We have here the removes of the children of Israel, till they came to the plains of Moab, from whence they passed over Jordan into Canaan. The end of their pilgrimage was near. "They set forward." It were well if we did thus; and the nearer we come to heaven, were so much the more active and abundant in the work of the Lord. The wonderful success God granted to his people, is here spoken of, and, among the rest, their actions on the river Arnon, at Vaheb in Suphah, and other places on that river. In every stage of our lives, nay, in every step, we should notice what God has wrought for us; what he did at such a time, and what in such a place, ought to be distinctly remembered. God blessed his people with a supply of water. When we come to heaven, we shall remove to the well of life, the fountain of living waters. They received it with joy and thankfulness, which made the mercy doubly sweet. With joy must we draw water out of the wells of salvation, ( Isaiah 12:3 ) . As the brazen serpent was a figure of Christ, who is lifted up for our cure, so is this well a figure of the Spirit, who is poured forth for our comfort, and from whom flow to us rivers of living waters, ( john 7:38 john 7:39 ) . Does this well spring up in our souls? If so, we should take the comfort to ourselves, and give the glory to God. God promised to give water, but they must open the ground. God's favours must be expected in the use of such means as are within our power, but still the power is only of God.