The forgiveness in this passage is hardly a free gift. The servant was forgiven because he did something. He pleaded.
We on the other hand do not plead for forgiveness. Our salvation is not based on whether we forgive. We simply believe what has been done on our behalf(1 Cor 15: 1-4), and we are more than forgiven.(Roms 4: 3-8)
The king freely forgave the man, because he humbled himself.
33 Should you not also have had compassion on your fellow servant, just as I had pity on you?'
34 And his master was angry, and delivered him to the torturers until he should pay all that was due to him.
35 So
My heavenly Father also will do to you if each of you, from his heart,
does not forgive his brother his trespasses.
Matthew 18:33-35
28 And even as
they did not like to retain God in their knowledge, God gave them over to a debased mind, to do those things which are not fitting;
29 being filled with all unrighteousness, sexual immorality, wickedness, covetousness, maliciousness; full of envy, murder, strife, deceit, evil-mindedness; they are whisperers,
30 backbiters, haters of God, violent, proud, boasters, inventors of evil things, disobedient to parents,
31 undiscerning, untrustworthy, unloving,
unforgiving, unmerciful;
32 who, knowing the righteous judgment of God,
that those who practice such things are deserving of death, not only do the same
but also approve of those who practice them. Romans 1:28-32
...unforgiving is ranked right in there with those who hate God.
The Gospel in Romans.
JLB