The Spirit himself bears witness with our spirit that we are children of God, and if children, then heirs. Paul links identity with inheritance here, you are not just acquitted, you are an heir.
Perhaps you know the moment when an old mistake resurfaces and feels current. But accusation has no right over a child of God. You are not the accused, you are an heir. The Spirit testifies to this in you, deeper than any voice of accusation.
Today you may live as an heir, with everything that entails.