Isaiah 43:1, 7, “But now, thus says the LORD, who created you, O Jacob,  And He who formed you, O Israel: ‘Fear not, for I have redeemed you; I have called you by your name; You are Mine’… ‘Everyone who is called by My name, Whom I have created for My glory; I have formed him, yes, I have made him.’ ”

Isaiah 43 reveals that God is talking to the entire nation of Israel. The name Jacob can refer to all of his decedents i.e., Israel. Isaiah 17:4, “In that day it shall come to pass that the glory of Jacob will wane, and the fatness of his flesh grow lean”; this cannot be referencing Jacob as he was already dead. 

God gave special promises to Abraham, Isaac, and Jacob and to all Israel. “In thee and in thy seed shall all the families of the earth be blessed…” Genesis 28:14. Of all the nations, God said, “You only have I known of all the families of the earth…” Amos 3:2. Therefore, verse 7 of Isaiah 43 is emphasizing this special relationship. God called the nation by His name, created them for His glory, and formed them.

Is Israel presently a glory to God? No, not yet. The nation will become God’s glory when they accept Jesus as their Savior and turn to God to direct their ways. Zechariah 12:10, 13:1, 14:8,9, (NASB) “I will pour out on the house of David and on the inhabitants of Jerusalem, the Spirit of grace and of supplication, so that they will look on Me whom they have pierced; and they will mourn for Him, as one mourns for an only son, and they will weep bitterly over Him like the bitter weeping over a firstborn…In that day a fountain will be opened for the house of David and for the inhabitants of Jerusalem, for sin and for impurity…And in that day living waters will flow out of Jerusalem…And the LORD will be king over all the earth; in that day the LORD will be the only one, and His name the only one.” 

A second line of reasoning: Were God to create each person separately, there would be a need for a separate redeemer for each person. God arranged it so that when Adam sinned, the death sentence came upon him and upon all of his children yet to be born. “As in Adam all die…” 1 Corinthians 15:22. Because each person is not on trial for life or death now but is dying through Adam, only one redeemer was necessary, the perfect man, Jesus Christ.  Jesus took Adam’s punishment of death upon Himself. Thereby, Jesus could redeem the entire human race through becoming the ransom for Adam (and all his children). “… in Christ shall all be made alive.” 1 Corinthians 15:22