When an employee works for an employer, the employer has a binding obligation to pay the employee the wages that are due for the time worked. This temporal concept, however, does not translate to the spiritual realm. When we stand before God on judgment day, we will not be able to present our works as justification for our salvation, because that implies that God has an obligation to accept those works. God is holy and just and our sin prevents Him from any obligation of saving us from an eternity apart from Him.
Thankfully God is also gracious and merciful and He freely gives salvation to those who simply believe on Him. Through Christ’s redemptive work, we can stand righteous before God, not because we can boast of our works (Romans 4:2), but purely because of His grace. Thank you, Jesus, for going to the cross on our behalf to redeem us from the penalty of our sin.