For what was impossible for the Torah—since it was weakened on account of the flesh—God has done. Sending His own Son in the likeness of sinful flesh and as a sin offering, He condemned sin in the flesh—
Romans 8:3 TLV

The Law is not weak in itself. As a reflection of God’s character, it is perfect. How could it condemn the entire human race if it were weak? The weakness is in the people who are unable to accept it on their hearts and keep it in their flesh. See Exodus 20:18-21.