Why is the Old Covenant not valid for Christians today?

The Old Covenant, established at Sinai, was contingent upon the people's ability to obey the law, a promise they definitively broke. Galatians 3:13 reveals that 'Christ hath redeemed us from the curse of the law,' emphasizing that believers in Christ are not under the law but under grace. The New Covenant, foretold by prophets like Jeremiah, provides a new basis of relationship with God through Jesus Christ, who perfectly fulfilled the law on our behalf. This transition is essential as it upholds God's justice while extending mercy and grace, highlighting our reliance on Christ's redemptive work rather than on our ability to obey the law.