Why is the God of the Old Testament so harsh and vindictive, and the God of the New Testament is both loving and merciful? It doesn’t seem like the same God to me.
Many people have thought this, but in fact the God of the Bible is the same throughout all the Scriptures. In both the Old and the New Testaments, God is loving and just. He is not merely wrathful in the Old Testament; He is loving and merciful and forgives sin, as in the example of David, who committed adultery and orchestrated the death of Uriah the Hittite. This description of God is found in the Old Testament: “The Lord, the Lord, the compassionate and gracious God, slow to anger, abounding in love and faithfulness, maintaining love to thousands, and forgiving wickedness, rebellion and sin” (Ex. 34:6–7).
The New Testament describes God’s justice as well as His love. He holds people accountable for their sin, and sometimes exercises discipline in seemingly severe ways. For example, when Ananias and Sapphira lied about how much they were giving to the congregation, Peter rebuked Ananias first, saying he had “not lied just to human beings but to God”—and then God struck him dead. The same then happened to his wife, Sapphira (Acts 5:1–11), reminiscent of instant justice sometimes seen in the Old Testament. The New Testament also describes the end of days, when God’s judgment will fall on the earth at the hands of Jesus, the Lamb of God. This is how people will respond in that day: “They called to the mountains and the rocks, ‘Fall on us and hide us from the face of him who sits on the throne, and from the wrath of the Lamb! For the great day of their wrath has come, and who can withstand it?’” (Rev. 6:16–17)? God is always the same. He is perfect and infinite in holiness and justice and in His love and mercy.