How do we know that true righteousness comes from Christ?

The Bible clearly teaches, as noted in Philippians 3:9, that we are to be found in Him, not having a righteousness of our own but that which comes through faith in Christ. The righteousness that God accepts must be perfect and complete, which is why our best deeds cannot earn God's favor. Only Jesus Christ, who lived without sin and fulfilled the law perfectly, possesses this righteousness. Therefore, those who believe in Him are clothed in His righteousness rather than their own inadequacies, ensuring their acceptance before God.