Answer
Many Jews in the time of the Old Testament did worship the true God. The God who called Abraham, gave the law to Moses, and established the nation of Israel is the One True God, eternal in the heavens. This is the same God that Christians worship today.
As an overview, here are some of the teachings about God that Jews and Christians share:
• God is eternal
• God is all-powerful
• God is all-present
• God is all-knowing
• Only one God exists
However, Judaism as practiced today does not worship the Christian God; that is, they do not worship the One True God of their ancestors. They have turned away from the truth of who God is.
Here are the main Christian teachings about God that set Christianity apart from Judaism:
• The one God exists in triunity (Father, Son, and Spirit)
• God became incarnate in the person of Jesus of Nazareth
The whole of the Old Testament—the revelation of the Old Covenant given to God’s chosen people, the Jews—points to the person and work and life of Jesus the Messiah (Luke 24:27). But when the Messiah came, “the world did not recognize him. He came to that which was his own, but his own did not receive him” (John 1:10–11). Because of their rejection of God’s Chosen One, Jesus pronounced judgment: “The kingdom of God will be taken away from you and given to a people who will produce its fruit” (Matthew 21:43; see also Matthew 11:20–24; 23:37–39; and Luke 19:41–44).
Many Jews today still intend to follow the Old Covenant, even though the sacrifices commanded in the Old Covenant cannot be offered today, and even though perfect observance of the Torah was never possible. Many Jews have missed the revelation of the Messiah and have failed to enter the New Covenant He sealed, even though that New Covenant was predicted far in advance (Jeremiah 31:31–34). The Jeremiah passage is quoted in the book of Hebrews, where the old is contrasted with the new: “In fact the ministry Jesus has received is as superior to [the high priests’ under the Mosaic Covenant] as the covenant of which he is mediator is superior to the old one, since the new covenant is established on better promises” (Hebrews 8:6).
Even in Jesus’ day, the Jewish religion had drifted from the Word of God, and the Jews were no longer worshiping God in truth. Jesus called out the religious leaders on several occasions, including when He said, “Isaiah was right when he prophesied about you hypocrites; as it is written: ‘These people honor me with their lips, but their hearts are far from me. They worship me in vain’” (Mark 7:6–7). Jesus then pinpointed the problem: “You have let go of the commands of God and are holding on to human traditions. . . . You have a fine way of setting aside the commands of God in order to observe your own traditions!” (Mark 7:8–9). According to Jesus, the religious leaders were not worshiping the true God; rather, they were making up their own rules and ignoring God’s—which is tantamount to worshiping oneself.
In confronting the religious error of His day, Jesus appealed to Moses: “Do not think I will accuse you before the Father. Your accuser is Moses, on whom your hopes are set. If you believed Moses, you would believe me, for he wrote about me. But since you do not believe what he wrote, how are you going to believe what I say?” (John 5:45–47). Moses knew and worshiped the One True God; the Jews of Jesus’ day did not. They kept the ceremonies and the form of the Jewish religion, but they rejected Christ, God’s own Son.
The apostle Paul, a Pharisee fully trained in the law of Moses, said of his Jewish brothers and sisters: “My heart’s desire and prayer to God for the Israelites is that they may be saved. For I can testify about them that they are zealous for God, but their zeal is not based on knowledge. Since they did not know the righteousness of God and sought to establish their own, they did not submit to God’s righteousness. Christ is the culmination of the law so that there may be righteousness for everyone who believes” (Romans 10:1–4). The crux of the difference between the God the Christians worship and the God the Jews worship is Christ.
As the prophecies had said, Jesus the Messiah became the Cornerstone that the builders rejected (Psalm 118:22; cf. Acts 4:11) and the Rock of Offense over which the Jews stumbled (Matthew 21:44; Luke 2:34; 1 Peter 2:7–8). But Jesus made it clear that He had not come to discard the Old Testament but to fulfill all that was written in it (Matthew 5:17–18). Jesus reveals to us who God is:
“Anyone who welcomes me welcomes the one who sent me” (Matthew 10:40)
“Whoever believes in me does not believe in me only, but in the one who sent me. The one who looks at me is seeing the one who sent me” (John 12:44–45)
“Whoever listens to you listens to me; whoever rejects you rejects me; but whoever rejects me rejects him who sent me” (Luke 10:16)
“I and the Father are one” (John 10:30)
So, do Jews and Christians worship the same God? For Jews and Christians who have faith in Jesus, yes, they worship the same God. Jesus is “the way, and the truth, and the life. No one comes to the Father except through [Him]” (John 14:6). For Jews who reject Jesus as the Messiah, it is unclear whether it is more accurate to say they are worshiping a false god or worshiping the one true God falsely. Whatever the case, Jews who reject Jesus are not worshiping God in the manner He requires. They have a tragically incomplete understanding of who God is, how He has provided salvation, and how to experience an intimate relationship with Him. The One True God has revealed Himself in Jesus Christ, “for in Christ all the fullness of the Deity lives in bodily form” (Colossians 2:9). Apart from faith in Christ, no one truly knows God.