The commentary on this section is helpful as well:
When Blessing Turns into Curse
The verses that follow form a great contrast with the previous verses. It is a dramatic section full of warnings. These are prophecies that have literally been fulfilled.
The interpretation of Scripture is threefold: literally in history, prophetically in the future and the spiritual or practical application for us. It is a serious section not only for Israel, but also for us. This section is also written that we may learn from it. In Romans 11 we hear the same warning and prophecy for Christianity (Rom 11:16-24 ). Christianity has experienced the same. The question is: What do we do with the lesson that this section contains?
In Deu 28:16-19 , everything in which the people in Deu 28:3-6 will be blessed by obedience is turned into a curse by disobedience. The curse runs parallel with the blessing. The curse hits them in the blessing. This is a penetrating presentation of the matter. From a spiritual point of view, we see that unfaithfulness causes the blessings to disappear – the insight in them and the enjoyment of them – and instead evil teachings come in, destroying the life of faith in every way.
7 My servant Moses is not so, who is faithful in all mine house.
Deuteronomy 7:9 (KJV)
9 Know therefore that the LORD thy God, he is God, the faithful God, which keepeth covenant and mercy with them that love him and keep his commandments to a thousand generations;
Deuteronomy 32:20 (KJV)
20 And he said, I will hide my face from them, I will see what their end shall be: for they are a very froward generation, children in whom is no faith.
Psalms 5:9 (KJV)
9 For there is no faithfulness in their mouth; their inward part is very wickedness; their throat is an open sepulchre; they flatter with their tongue.
Psalms 31:23 (KJV)
23 O love the LORD, all ye his saints: for the LORD preserveth the faithful, and plentifully rewardeth the proud doer.
The ONLY way to demonstrate faith is to KEEP THE LAW.
Everything else is fake faith.
Matthew 5:17-20 --
17 Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil.
18 For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled.
19 Whosoever therefore shall break one of these least commandments, and shall teach men so, he shall be called the least in the kingdom of heaven: but whosoever shall do and teach them, the same shall be called great in the kingdom of heaven.
20 For I say unto you, That except your righteousness shall exceed the righteousness of the scribes and Pharisees, ye shall in no case enter into the kingdom of heaven.
That is the KJV, but the Expanded Bible is even more clear:
17 “Don’t think that I have come to ·destroy [abolish; do away with] ·the law of Moses or the teaching of the prophets [L the Law and the Prophets; C referring to the OT]. I have not come to destroy them but to ·bring about what they said [fulfill/complete them].
18 I tell you the truth, until heaven and earth ·are gone [pass away; disappear], not even ·the smallest letter [T one jot; L one iota; C the smallest Greek letter] or the smallest ·part [stroke; T tittle] of a letter will ·be lost [pass away; disappear] until everything ·has happened [is accomplished/achieved].
19 [L Therefore] Whoever ·refuses to obey [ignores; breaks; annuls] ·any command [L one of the least of these commands] and teaches other people ·not to obey that command [L to do likewise] will be ·the least important [L called/considered least] in the kingdom of heaven. But whoever ·obeys [keeps; practices] the commands and teaches other people to obey them will be [considered; L called] great in the kingdom of heaven.
20 [L For] I tell you that ·if you are no more obedient than [L unless your righteousness surpasses/exceeds that of] the ·teachers of the law [scribes] and the Pharisees, you will ·never [or certainly not] enter the kingdom of heaven.
You demonstrate your faith by KEEPING THE LAW.
It is as simple as that.
All this false church doctrine of "good works" or "saved by grace alone" or "saved by faith alone" misses the point.
You demonstrate to whom? Others. God doesn't need a demonstration. Nothing saves you apart from Jesus christ. You can either accept his gift or not. Nothing you do, including following the law saves you. You follow the law becuase you love God. If you sin again, you are still saved.
Deuteronomy 28:1-14 = Blessings for Obedience
Deuteronomy 28:15-68 = Curses for Disobedience
The commentary on this section is helpful as well:
When Blessing Turns into Curse
The verses that follow form a great contrast with the previous verses. It is a dramatic section full of warnings. These are prophecies that have literally been fulfilled.
The interpretation of Scripture is threefold: literally in history, prophetically in the future and the spiritual or practical application for us. It is a serious section not only for Israel, but also for us. This section is also written that we may learn from it. In Romans 11 we hear the same warning and prophecy for Christianity (Rom 11:16-24 ). Christianity has experienced the same. The question is: What do we do with the lesson that this section contains?
In Deu 28:16-19 , everything in which the people in Deu 28:3-6 will be blessed by obedience is turned into a curse by disobedience. The curse runs parallel with the blessing. The curse hits them in the blessing. This is a penetrating presentation of the matter. From a spiritual point of view, we see that unfaithfulness causes the blessings to disappear – the insight in them and the enjoyment of them – and instead evil teachings come in, destroying the life of faith in every way.
Not really about faith.
It is about punishment for disobeying God's law.
"Do this, and this is your reward."
"Don't do it, and this is your punishment."
Same relationship as a parent and child.
Simple as that.
It is always about faith.
Faith is mentioned 58 times in the Old Testament.
Numbers 12:7 (KJV)
7 My servant Moses is not so, who is faithful in all mine house.
Deuteronomy 7:9 (KJV)
9 Know therefore that the LORD thy God, he is God, the faithful God, which keepeth covenant and mercy with them that love him and keep his commandments to a thousand generations;
Deuteronomy 32:20 (KJV)
20 And he said, I will hide my face from them, I will see what their end shall be: for they are a very froward generation, children in whom is no faith.
Psalms 5:9 (KJV)
9 For there is no faithfulness in their mouth; their inward part is very wickedness; their throat is an open sepulchre; they flatter with their tongue.
Psalms 31:23 (KJV)
23 O love the LORD, all ye his saints: for the LORD preserveth the faithful, and plentifully rewardeth the proud doer.
Yes, faithful ... to THE LAW.
The ONLY way to demonstrate faith is to KEEP THE LAW.
Everything else is fake faith.
Matthew 5:17-20 --
That is the KJV, but the Expanded Bible is even more clear:
You demonstrate your faith by KEEPING THE LAW.
It is as simple as that.
All this false church doctrine of "good works" or "saved by grace alone" or "saved by faith alone" misses the point.
You demonstrate to whom? Others. God doesn't need a demonstration. Nothing saves you apart from Jesus christ. You can either accept his gift or not. Nothing you do, including following the law saves you. You follow the law becuase you love God. If you sin again, you are still saved.