The continuity between the mercy of God in Christ Jesus and the justice of God in the Law of Moses is beautifully one truth.
In the New Testament Paul, the apostle of grace to the gentiles, made some authoritative declarations that leave us wondering just how he could be so strong.
For example in Galatians Paul wrote - " If anyone is preaching a gospel contrary to what we preached to you, let him be accursed.” He even used the same word "ἀνάθεμα” when concluding his first letter to Corinth - "If anyone does not love the Lord, let him be ἀνάθεμα - accursed”
How could Paul be so bold to make such a severe declaration? If we knew the scriptures as well as he did, we would understand. Paul simply used the very same word found in Deuteronomy that addressed the very same issue.
Moses wrote that if news came to the people of a city whose men had departed from the Lord and had begun to worship different gods, a thorough investigation must take place. If the report was found to be true beyond doubt, the city and all the residents living there, were to be ἀνάθεμα ἀνάθεμα.
Our God is the same yesterday, today, and forever. People who know better and willingly depart from Him will receive severe and final destruction. Our Lord did not come to abolish commands such as this severe edict - He came to fulfill them. Therefore we must give the more earnest heed to the things we have heard, lest we drift away. For if the word spoken through angels proved steadfast, and every transgression and disobedience received a just reward, how shall we escape if we neglect so great a salvation,