When Pandvas left for Himalaya, King Parikshit was crowned as the King of Hastinapur. One fine day King Parikshit went for hunting and saw a strange sight: a Chandaal was killing a cow by breaking her bones, [cow was (is) considered a holy being so any attack on cow means death on the attacker] Parikshit gave a warning to the chandaal and raised his sword to behead him.
Chandaal said “ oh great King, please listen to my words first and then take the decision to kill me or not".
Parikshit said "what do you want to tell me, your deeds are a call to death there is nothing which can save you now, but still I’ll give you a chance to speak", Chandaal said “ great King I am Kali (not Kaali the goddess) the cause of Kaliyug and this cow is embodiment of Dharma, I am here to kill dharma. I have broken her three legs which represent truth, honesty, and mercy, I will also break the fourth leg that is faith. It is my sole purpose for which I was created, so let me do my duty and don't interfere in divine actions."
After listening these words Parikshit was enraged and said, "Kali, you forgot that it is the duty of King to save his subjects, and after all you are destroying dharma which multiplies your sin, I will not spare you.”
Kali requested him, "if you want to fight with me I am ready to fight with you but please listen my single virtue first then decide.“
Parikshit said, "if that is your last wish it's fine go ahead.”
Kali said, "oh great King you must have heard many bad things about me but my single largest virtue is that who so ever takes the name of God 120 times with pure heart and with complete dedication will get the punya equivalent to 12 years of penance during Kaliyug."
Now Parikshit softened a bit and said, "Indeed I have heard a lot of bad things about you but, this virtue of yours sounds too good. It must be true because in Tretayug several thousands of years of penance was needed to attain moksha, in Satyug several hundreds of years of penance was needed to attain moksha, in Dwaparyug we need many years of penance to attain moksha, so in your time only some days, this means you will prove to be useful for coming generation. I can spare your life but only on one condition that you will leave this cow/dharma and I will also grant you anything in return.”
Kali replied, "oh great and generous King I’ll leave this cow for once but as you promised me give me the boon to reside in gold.”
Parikshit granted the boon and Kali immediately entered into the golden crown of King and said, "oh generous King how can you think that people will attain moksha in Kaliyug within few days when I will not allow people to meditate on God for even an hour?”
This is the power of Kaliyug he broke truth, honesty and mercy, now dharma stands only on faith.
(Taken from Quora)