"[The LORD] brought Abram out, and said : Look to the heavens and count the stars, if you can count them. And he said unto him, Thus shall thy seed be. And he believed the LORD ... and the LORD made a covenant with Abram, saying : I give this land unto thy seed." Genesis 15: 5-18
"Now ... if you keep my covenant ... you will be a kingdom of priests and a holy nation to me." Exodus 19: 5, 6 (KJV)
God loves this people whose creation he announces, and the voice he utters at Abram has such power that it gives rise to a certainty. Abram believes God on his word, even though he and Sara are no longer of child-bearing age. Twice already God had promised Abram a progeny and the possession of the land of Canaan (Gen. 12: 2, 7, 13. 14-16). These two promises, God renews them by changing his name to Abraham (father of a multitude) and guarantees them by an unconditional alliance (Gen. 17: 5).
But this unconditional promise made to Abraham in no way removes human responsibility (second passage of the day). The sons of Israel come out of Egypt like the people of the Lord, and come to Sinai, where God reveals himself to them in his majesty and sovereignty. They commit themselves with one voice to obey all the words of the Lord : "All that the Lord has said, we will do" (Exodus 19: 8). This means that the divine blessing will depend on their obedience to God! Consequently, their infidelities will result in judgments which God, the initiator of the covenant, announces in the book of Deuteronomy. These curses will affect men and the country itself : history has largely confirmed this. The long exile announced is a striking example of it by its painful reality still today. "The LORD will scatter you among all the peoples from one end of the earth to the other side of the earth ... And among these nations you will have no peace ..." (Deut.28, 64, 65).
The survival of the Jewish people during this long diaspora is the "result" of this double blessing, unconditional towards Abraham and conditional on Israel. This people still has a role to play as a nation and the providence of God has allowed it to keep its identity even by going through the announced judgments. If today men are astonished at Zionism, it is because they ignore the Word of God : "My counsel shall be fulfilled ... My salvation shall not be long ; and I set my salvation in Zion, and my glory on Israel" (Isaiah 46: 10-13).
Source (To pleasing the Lord)