v1-3: Commandments for the promised land, and blessings for the obedient.

The people were to "observe" (or "to do") the commandments, and to keep them. The specific blessing was that their days would be prolonged, or protected - and God would do this. This was the reward from God, not simply an inevitable consequence of obedience. They had to be careful to obey, which infers a diligence and commitment - the blessing was that it would go well with them, and that they would be fruitful in the fruitful land.

v4-5: The summary of the law was love for God. The N.T. teaches that love for God is the fulfilment of the law, Rom 13.10. Almighty God demands obedience from those who belong to Him. Such love is our proper response to God. It is a love of quality, of devotion, of intimacy, of exuberance; “I am faint (or sick) with love” (Song 2.5).

The Lord Jesus Christ said that this was the first and greatest commandment.

This 'Shema,' (v4-9) is the heart of the Jewsih creed, recited daily, taught from birth. Everything else flowed from these few verses. Orthodox Jews literally tied small boxes on their foreheads in obedience to this command. 

v6: God's commandments were to be on their hearts; 4.9; 5.29 - this was the only way that there would be real obedience. The same is true for the Christian.

v7-9: The Israelites had to become familiar with the words of God, and pass them on. Let the word of Christ dwell richly.

The things of God should be our conversation. This is a good example to young Christians; it is a testimony to unbelievers. Also, when difficulties arise, as is promised, we will more naturally look to God for answers.

This 'Mesusah' was like a phylactery for the house. Dr Edersheim comments that it 'served a purpose kindred to that of the phylactery for the person, both being derived from a misunderstanding and misapplication of the Divine direction' here. (Sketches of Jewish Social Life) Originally, the Mesusah was a symbol of the presence of God (Ps 121.8), it became something of a superstition at the time of Christ.

v10-12: The dangers of prosperity and comfort. Although the Lord God would give His people great riches, they had to learn to constantly trust in Him, not in what He gave them. In particular, they had to remember that they had been delivered from slavery in Egypt, by God's grace and power.

v13: The simple, explicit command was to fear God, serve Him, and take oaths only in His Name. This was to be a deliberate commitment to God.

v14-15: The people were to avoid idolatry, for God is a jealous God, 4.24; 5.9. The temptations were all around, for all other nations pursued idolatry in some form. The influence of other nations had to be carefully avoided.

Christians may not come across such forms of idolatry, but temptation in obvious and subtle forms is all around. The temptations are not just to do wrong things, but to take on the attitudes and thoughts of the ungodly; see Col 3.5, which refers to wrong actions, and Col 3.8 which refers to wrong words and attitudes.

v16-17:   There were past mistakes to learn from; we are not bound to repeat yesterday’s mistakes. Rather we must “be sure” to obey what God has declared.

v18-19: The best way to avoid wrong-doing is to do the right thing; obedience was the route to blessing. The blessing here is that the enemies of Israel would be cast out of the land.

v20-22: The deliverance from Egypt was the basis of the people's love and obedience; see 5.6. This was why they were commanded to remember this work of God, with signs and wonders.

For the Christian, redemption by faith in Christ is the beginning; we love Him who first loved us; we obey Him out of gratefulness.

v23: Perhaps the key verse in Deuteronomy; "He brought us out...to bring us in"; the deliverance from Egypt was the first part of God's wonderful salvation for His people. The deliverance into the land of Canaan was the second part - the delay was solely due to the people's disobedience. They missed out on blessing because of their disobedience.

The deliverance from Egypt was a fact, and it was accomplished by God. The reason was, first, that He light bring them into the inheritance of Canaan, and, second, that He might fulfil the promises made to Abraham, Isaac, and Jacob.

In prophecy, a similar promise was given to the people of Israel who had been scattered, that God would bring them back; Ezek 34.13.

v24: Life and prosperity came by obedience.

v25: Righteousness was by the law, for the people had committed themselves to the Covenant of the Law. This was something wonderful, as the Gentile nations lived in unrighteousness.

For the Christian, Christ has obeyed on our behalf, and we receive the righteousness of God, apart from the law, in Him.