I will put this out there for serious consideration; if, as some insist, the promises to Israel are only to the nation of Israel, then where did those promises come from? WHY did God help Israel and give them Moses and take them out of Egypt in the first place and lead them to Canaan?
The answer of course is that He did it to fulfill His everlasting covenant with Abraham. The covenant with Israel (which is not the covenant He wanted to make, but was a concession to their pride (He said I am poised to make you a nation of Kings of Priests, and they said, whatever you have for us to do, we are well-able to do it, so they removed themselves from the covenant of grace and forced God to make a covenant of Law with them so they could earn the blessing rather than get it like they had been, through grace (favor)) is the fulfillment of the covenant with Abraham and is therefore a continuation of the original covenant with Abraham.
Then when Jesus comes, He is the final fulfillment of both covenants, though it started with Abraham.
God did not bless the "nation" of Abraham, He blessed HIM. Just as He did not bless the nation of Isaac, but blessed Isaac himself.
Jacob/Israel was blessed HIMSELF, and so were all his seed. It was by birth, if you were of the bloodline of Abraham, you had the blessing of the Lord on you.
Then people say foolish things like, well if the Blessing makes you rich, why isn't EVERY Believer rich, since that's God's perfect will?
Then we have to ask since God's perfect will is that EVERONE knows Him and receives Christ, why isn't EVERYONE saved yet? That's God's will after all - He is not willing that ANY should perish. Yet we know that we have billions of earthlings who do NOT know God or Jesus. How is this possible if God's will is for ALL mankind to come to Christ.....hmmm....?
If God's perfect will is that no one is ever abused/hurt/harmed, etc, then how is it that people suffer these things...and "good" people too...even Christians...? For God's perfect will is Heaven, where no one is ever harmed, just like in Eden...yet how can it be so...?
Is is possible that just because something is God's will, it doesn't mean that it is AUTOMATIC?
God's will is that all be saved, yet that is not automatic, it took us acting in faith and receiving what He had already done and the Word became salvation to us...
In the same way, God's people the Israelites were in Egypt, in God's will in that they were His people through the covenant with Abraham. Yet they suffered slavery and did not even own their own bodies and never had enough (and yet it took over 400 years until SOMEONE called out in faith to God...astounding!).
Then they are brought out with miracles and into the wilderness where they have just enough, and God does fabulous things on this short journey, yet all the while He is letting them know it is not His perfect will, but that He has a place He calls the Promised Land (promised to who? ABRAHAM) which is Canaan the land of abundance, of always more than enough.
Then they come to Canaan, and they give an evil unbelieving report of what God has called good and they cannot enter because of unbelief. Was that God's will that they wander for 40 years while the unbelieving people of God's people died off? He said it wasn't.
Yet their unbelief is recorded for us it says in 1 Cor 10 to serve as an example for us that we may not miss out on God's perfect will as they did.
See also Hebrews 3 and 4 for this too (and note that God says the GOSPEL was preached unto them - the Blessing).
God's will was that MOSES go into the Promised Land, but Joshua did it instead because Moses disqualified himself. God's will was that the journey to the Promised Land took about a week or so, but the people disqualified themselves through their unbelief and their gainsaying of God, insisting that if what God said was true they'd have all seen it by now and it would be upon them all already...
Again, all of that stuff given to them was from God's covenant with Abraham and God relates to them what life is like under the Blessing of the Lord vs what is like under the curse. WHO gave the tithes by the way? Was it a national tithe or did each individual come and bring their tithes? And when God is rebuking the PEOPLE in verse 8 of Malachi 3, He says it is the men who are doing it, even the entire nation (meaning the priests are included) and then they say, how are WE robbing You? If God wanted to correct them and say, "I did not say you individuals, I meant you Israel as a nation only" He would have, yet He does not and leaves it as INDIVIDUALS.
The individuals of the nation of God's people make up the nation...What was going to happen to Abraham as a result of the everlasting covenant (notice God said it was an EVERLASTING covenant - it did not end, it was fulfilled with Jesus' new covenant, and we are back to receiving the Blessing as Abraham did, in faith because of God's grace)? He was going to have children, who would have more children, etc, and even though they comprised a nation of people they were blessed individually through the covenant. How was Jesus blessed? If HE was blessed, and now you are one with Him, a joint heir with Him (Romans 8:17), and you ARE as He IS NOW in THIS WORLD (1 John 4:17) - then...YOU ARE BLESSED, even apart from everything else I've already explained, you must see this. Is Jesus blessed? Then SO ARE YOU, or the Word of God is wrong (and that obviously is not an option).
We are warned to not miss out on God's good, acceptable and perfect will (Romans 12 - why doesn't He just say will, why does He add good and acceptable and perfect - and why does He say YOU prove it (like Joshua 1:8)?) like they did, because even when they got into the Promised Land, only JUDAH did what God's perfect will was - to possess everything there and have much more than enough. They could have been like the other unbelieving tribes of God's people that Joshua had to go rebuke over their refusal to go possess it once within it.
It is the same today, if you want to take God at His Word and receive all that He's promised to you, you may, and He is glad to do it. OR you can believe Satan's lies about disqualifying you from everything and only getting things when you get to Heaven...it's up to you, because as Romans 12 says, YOU will prove what is that good and acceptable and perfect will of God, not Him (in other words, IT'S NOT AUTOMATIC). Will you believe God's Word or man's vain philosophies and traditions and opinions that SPOIL you (Colossians 2:8)?