21:1-3 Before the people began their march round the country of Edom, the king of Arad, a Canaanite, who inhabited the southern part of the country, attacked them in the wilderness, and took some prisoners. This was to lead the Israelites to look more thoroughly to the Lord.
21:4-9 The children of Israel were wearied by a long march round the land of Edom. They speak discontentedly of what God had done for them, and distrustfully of what he would do. What will they be pleased with, whom manna will not please? Let not the contempt which some cast on the word of God, make us value it less. It is the bread of life, substantial bread, and will nourish those who by faith feed upon it, to eternal life, whoever may call it light bread. We see the righteous judgment God brought upon them for murmuring. He sent fiery serpents among them, which bit or stung many to death. It is to be feared that they would not have owned the sin, if they had not felt the smart; but they relent under the rod. And God made a wonderful provision for their relief. The Jews themselves say it was not the sight of the brazen serpent that cured; but in looking up to it, they looked up to God as the Lord that healed them. There was much gospel in this. Our Saviour declared, Joh 3:14,15, that as Moses lifted up the serpent in the wilderness, so the Son of man must be lifted up, that whatsoever believeth in him, should not perish. Compare their disease and ours. Sin bites like a serpent, and stings like an adder. Compare the application of their remedy and ours. They looked and lived, and we, if we believe, shall not perish. It is by faith that we look unto Jesus, Heb 12:2. Whosoever looked, however desperate his case, or feeble his sight, or distant his place, was certainly and perfectly cured. The Lord can relieve us from dangers and distresses, by means which human reason never would have devised. Oh that the venom of the old serpent, inflaming men's passions, and causing them to commit sins which end in their eternal destruction, were as sensibly felt, and the danger as plainly seen, as the Israelites felt pain from the bite of the fiery serpents, and feared the death which followed! Then none would shut their eyes to Christ, or turn from his gospel. Then a crucified Saviour would be so valued, that all things else would be accounted loss for him; then, without delay, and with earnestness and simplicity, all would apply to him in the appointed way, crying, Lord, save us; we perish! Nor would any abuse the freeness of Christ's salvation, while they reckoned the price which it cost him.
21:10-20 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, Isa 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, Joh 7:38,39. 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.
21:21-35 Sihon went with his forces against Israel, out of his own borders, without provocation, and so ran upon his own ruin. The enemies of God's church often perish by the counsels they think most wisely taken. Og, king of Bashan, instead of being warned by the fate of his neighbours, to make peace with Israel, makes war with them, which proves in like manner his destruction. Wicked men do their utmost to secure themselves and their possessions against the judgments of God; but all in vain, when the day comes on which they must fall. God gave Israel success, while Moses was with them, that he might see the beginning of the glorious work, though he must not live to see it finished. This was, in comparison, but as the day of small things, yet it was an earnest of great things. We must prepare for fresh conflicts and enemies. We must make no peace or truce with the powers of darkness, nor even treat with them; nor should we expect any pause in our contest. But, trusting in God, and obeying his commands, we shall be more than conquerors over every enemy.