"Yet now hear, O Jacob my servant; and Israel, whom I have chosen: Thus saith the LORD that made thee, and formed thee from the womb, which will help thee; Fear not, O Jacob, my servant; and thou, Jesurun, whom I have chosen. For I will pour water upon him that is thirsty, and floods upon the dry ground: I will pour my spirit upon thy seed, and my blessing upon thine offspring: And they shall spring up as among the grass, as willows by the water courses." (Isaiah 44:1-4)
Jesurun means upright one. The use of this term is interesting, especially when considering the idolatry with which Israel struggled throughout Isaiah's ministry. The same name is given to Israel in Deuteronomy 32:15 where Israel's departure from God is foretold. Israel has no uprightness or righteousness of her own; rather, she looks forward to God's righteousness which will be imparted to her at the commencement of the millennial kingdom. Because the nation has been chosen of God, the Lord refuses to forsake her; and He intends to redeem her. The spiritual awakening of the nation will be seen when God's Spirit is poured upon the Jews because of their belief in Jesus Christ. The spiritually thirsty ground will be well-watered by the fountain which will be opened to the house of David for sin and uncleanness (Zechariah 13:1). Through the salvation of the Jews and Gentiles in the Church age, one sees small illustrations of what God will do with Israel when the promises of these verses are completely fulfilled at Christ's second coming.
Belief in the merit of Christ's blood can take a hopelessly corrupt sinner and transform him into the upright one of God (Romans 8:1-4).