Works will come into consideration as a manifestation of genuine saving faith. Work in the scriptural sense also means not just an external display but the expression of one’s life that flows out of the depth of the heart….
Scripture also speaks of reward for believers (“their works follow them,” Rev 14:13; Matt 5:12, 16; 6:1; Luke 6:23; Heb 10:34–38). This reward comes as compensation for the cross, as restitution for what was robbed, as recompense for love shown to the servants of the Lord, etc….
Geerhardus Vos, Reformed Dogmatics, 5.293