How do we know that God sees no iniquity in believers?

In Numbers 23, Balaam proclaims that God has not beheld iniquity in Jacob, which is a profound declaration for believers who are united with Christ. God does not see our sins as He views us through the righteousness of Christ, as illustrated in 2 Corinthians 5:21, which says that 'He made Him to be sin for us who knew no sin, that we might be made the righteousness of God in Him.' This underscores the truth that believers are positionally righteous before God, with their sins forgiven and forgotten in Christ's redemptive work.