This peculiarity in the land of Canaan led Moses to close the first part of his discourse on the law, his exhortation to fear and love the Lord, with a reference to the blessing that would follow the faithful fulfilment of the law, and a threat of the curse which would attend apostasy to idolatry.
If Israel would serve its God in love and faithfulness, He would give the land early and latter rain in its season, and therewith a plentiful supply of food for man and beast (see Lev 26:3 and Lev 26:5; and for the further expansion of this blessing, Deu 28:1-12).
But if, on the other hand, their heart was foolish to turn away from the Lord and serve other gods, the wrath of the Lord would burn against them, and God would shut up the heaven, that no rain should fall and the earth should yield no produce, and they would speedily perish (cf. Lev 26:19-20, and Deu 28:23-24). Let them therefore impress the words now set before them very deeply upon themselves and their children (Deu 11:18-21, in which there is in part a verbal repetition of Deu 6:6-9). The words, “as the days of the heaven above the earth,” i.e., as long as the heaven continues above the earth, - in other words, to all eternity (cf. Psa 89:30; Job. Deu 14:12), - belong to the main sentence, “that your days may be multiplied,” etc. (Deu 11:21). “The promise to give the land to Israel for ever was not made unconditionally; an unconditional promise is precluded by the words, 'that your days may be multiplied'” (Schultz). (For further remarks, see at Deu 30:3-5.) For (Deu 11:22-25) if they adhered faithfully to the Lord, He would drive out before them all the nations that dwelt in the land, and would give them the land upon which they trod in all its length and breadth, and so fill the Canaanites with fear and terror before them, that no one should be able to stand against them. (On Deu 11:23, cf. Deu 7:1-2; Deu 9:1, and Deu 1:28.) The words, “every place whereon the soles of your feet shall tread shall be yours,” are defined more precisely, and restricted to the land of Canaan on both sides of the Jordan by the boundaries which follow: “from the desert (of Arabia on the south), and Lebanon (on the north), and from the river Euphrates (on the east) to the hinder sea” (the Mediterranean on the west; see Num 34:6). The Euphrates is given as the eastern boundary, as in Deu 1:7, according to the promise in Gen 15:18. (On Deu 11:25, cf. Deu 7:24; Deu 2:25, and Exo 23:27.)
Concluding summary. “I set before you this day the blessing and the curse.” The blessing, if (אֲשֶׁר, ὅτε, as in Lev 4:22) ye hearken to the commandments of your God; the curse, if ye do not give heed to them, but turn aside from the way pointed out to you, to go after other gods. To this there are added instructions in Deu 11:29 and Deu 11:30, that when they took possession of the land they should give the blessing upon Mount Gerizim and the curse upon Mount Ebal, i.e., should give utterance to them there, and as it were transfer them to the land to be apportioned to its inhabitants according to their attitude towards the Lord their God. (For further comment, see at Deu 27:14.) The two mountains mentioned were selected for this act, no doubt because they were opposite to one another, and stood, each about 2500 feet high, in the very centre of the land not only from west to east, but also from north to south. Ebal stands upon the north side, Gerizim upon the south; between the two is Sichem, the present Nabulus, in a tolerably elevated valley, fertile, attractive, and watered by many springs, which runs from the south-east to the north-west from the foot of Gerizim to that of Ebal, and is about 1600 feet in breadth. The blessing was to be uttered upon Gerizim, and the curse upon Ebal; though not, as the earlier commentators supposed, because the peculiarities of these mountains, viz., the fertility of Gerizim and the barrenness of Ebal, appeared to accord with this arrangement: for when seen from the valley between, “the sides of both these mountains are equally naked and sterile;” and “the only exception in favour of the former is a small ravine coming down, opposite the west end of the town, which is indeed full of foundations and trees” (Rob. Pal. iii. 96, 97). The reason for selecting Gerizim for the blessings was probably, as Schultz supposes, the fact that it was situated on the south, towards the region of the light. “Light and blessing are essentially one. From the light-giving face of God there come blessing and life (Psa 16:11).” - In Deu 11:30 the situation of these mountains is more clearly defined: they were “on the other side of the Jordan,” i.e., in the land to the west of the Jordan, “behind the way of the sunset,” i.e., on the other side of the road of the west, which runs through the land on the west of the Jordan, just as another such road runs through the land on the east (Knobel). The reference is to the main road which ran from Upper Asia through Canaan to Egypt, as was shown by the journeys of Abraham and Jacob (Gen 12:6; Gen 33:17-18). Even at the present day the main road leads from Beisan to Jerusalem round the east side of Ebal into the valley of Sichem, and then again eastwards from Gerizim through the Mukra valley on towards the south (cf. Rib. iii. 94; Ritter, Erdkunde, xvi. pp. 658-9). “In the land of the Canaanite who dwells in the Arabah.” By the Arabah, Knobel understands the plain of Nabulus, which is not much less than four hours' journey long, and on an average from a half to three-quarters broad, “the largest of all upon the elevated tract of land between the western plain and the valley of the Jordan” (Rob. iii. p. 101). This is decidedly wrong, however, as it is opposed to the fixed use of the word, and irreconcilable with the character of this plain, which, Robinson says, “is cultivated throughout and covered with the rich green of millet intermingled with the yellow of the ripe corn, which the country people were just reaping” (Pal. iii. 93). The Arabah is the western portion of the Ghor (see at Deu 1:1), and is mentioned here as that portion of the land on the west of the Jordan which lay stretched out before the eyes of the Israelites who were encamped in the steppes of Moab. “Over against Gilgal,” i.e., not the southern Gilgal between Jericho and the Jordan, which received its name for the first time in Jos 4:20 and Jos 5:9; but probably the Gilgal mentioned in Jos 9:6; Jos 10:6., and very frequently in the history of Samuel, Elijah, and Elisha, which is only about twelve and a half miles from Gerizim in a southern direction, and has been preserved in the large village of Jiljilia to the south-west of Sinjil, and which stands in such an elevated position, “close to the western brow of the high mountain tract,” that you “have here a very extensive prospect over the great lower plain, and also over the sea, whilst the mountains of Gilead are seen in the east” (Rob. Pal. iii. 81). Judging from this description of the situation, Mount Gerizim must be visible from this Gilgal, so that Gerizim and Ebal might very well be described as over against Gilgal.
(Note: There is much less ground for the opinion of Winer, Knobel, and Schultz, that Gilgal is the Jiljule mentioned by Robinson (Pal. iii. 47; and Bibl. Researches, p. 138), which evidently corresponds to the Galgula placed by Eusebius and Jerome six Roman miles from Antipatris, and is situated to the south-east of Kefr Saba (Antipatris), on the road from Egypt to Damascus. For this place is not only farther from Gerizim and Ebal, viz., about seventeen miles, but from its position in the lowland by the sea-shore it presents no salient point for determining the situation of the mountains of Gerizim and Ebal. Still less can we agree with Knobel, who speaks of the village of Kilkilia, to the north-east of Kefr Saba, as the name itself has nothing in common with Gilgal.)
The last definition, “beside the terebinths of Moreh,” is intended no doubt to call to mind the consecration of that locality even from the times of the patriarchs (Schultz: see at Gen 12:6, and Gen 35:4).
Deu 11:31-32 contain the reason for these instructions, founded upon the assurance that the Israelites were going over the Jordan and would take possession of the promised land, and should therefore take care to keep the commandments of the Lord (cf. Deu 4:5-6).