How do we know Jesus fulfilled the law perfectly?

The belief that Jesus fulfilled the law perfectly comes from the understanding that He walked without sin and obeyed God’s commands completely. Psalm 1 illustrates this by highlighting a blessed man who does not walk in the counsel of the ungodly—this description perfectly applies to Christ. As He lived among humanity, He demonstrated perfect obedience to God's law, even unto death on the cross. Furthermore, His fulfillment of the law is confirmed in the New Testament, such as in Matthew 5:17 where He states He came not to abolish the law but to fulfill it. This perfect righteousness is then imputed to believers, providing assurance of their standing before God.