In chapter 23 of the book of Joshua we find how God through Joshua exhorts His people to keep His words and not contaminate with other nations, since that would serve as a stumbling. Throughout the Scriptures God always guided His people so that they would not allow themselves to be influenced by other nations, in the same way He does not want us to allow ourselves to be clothed by the system of this world.
After God had exhorted the people of Israel to keep His commandments, to fulfill the laws of Moses and not to mingle with the other nations, He reminded them of all the good words He had said about them and how each one was fulfilled to the letter:
Now I am about to go the way of all the earth. You know with all your heart and soul that not one of all the good promises the Lord your God gave you has failed. Every promise has been fulfilled; not one has failed.
God had made multiple promises to His people Israel, and all those good words that He had said had been fulfilled. We must understand something about the character of God, and is that He is not like us, when God promises something He fulfills it. The people of Israel had to remember how God brought them out with the mighty hand from Egypt, how He divided the sea, as He accompanied them day and night with incredible signs and wonders. Simply this people could not forget all that God had done for them.
Perhaps you will say: “What a privileged people”. Did you know that we are more privileged than them? And it is that God has loved us when we were in our crimes and sins, and He has given us salvation through the death of His Son on the cross and there is no greater miracle than the miracle of salvation in Christ.
The Word of God is infallible, and all the promises that God has made to His people through His Word must be fulfilled.