Lord Shiva and Shri Krishna are adorable to each other and reside in each other's heart. Just as Mahadev meditates every moment by remembering the image of Shri Krishna, in the same way Shri Krishna also gets engrossed in the meditation of Mahadev.
It is also mentioned in religious and mythological stories that how both have always helped each other for the benefit of the world and created unique and wonderful pastimes.
There was little time left at the end of Dwaparak Yuga when the war of Mahabharata took place. It is known in the Mahabharata book that how fierce and destructive this war was. After this war, that land of Kurukshetra had become completely red. Even that part of the battlefield is still red after all these ages. The war ended and there was victory of righteousness over unrighteousness, but this war had such an effect on the whole world that the circulation of negative energy increased from Earth to Amber and people started fighting to get their share of land or anything.
Lord Shiva was extremely sad to see such a scene on earth. All the gods and goddesses also reached Mahadev to talk to Shri Krishna about this. Then Mahadev left for Indraprastha situated on the earth. Mahadev reached before Shri Krishna. Shri Krishna also became very emotional after seeing his adorable.
Lord Shiva knew that Ashwamedha Yagya is the only way to destroy the negativity of the world. But he also knew that Shri Krishna would never agree to Ashwamedh Yagya. The reason behind this was that during the Ashwamedha Yajna the sacrificial horse is released to roam the earth. The place through which the horse passes becomes under the control of the king performing the Ashwamedha Yajna and when the horse returns If tax comes, then that horse is sacrificed.
The Ram avatar of Lord Vishnu had sacrificed a horse but this was never acceptable to Shri Krishna.
When Mahadev saw Shri Krishna emotional, he started trying but Shri Krishna understood his intention. After this, on the clear asking of Shri Krishna, Mahadev urged him to perform Ashwamedha Yagya, which Shri Krishna refused.
After tireless efforts, Baldau and Mahadev reached the final decision that Shri Krishna himself should not perform the Ashwamedh Yagya and get it done by someone else, but he should participate in that Yagya. Since Shri Krishna is the divine incarnation, his presence also makes this yagya as effective as his performance of this yagya.
Mahadev spoke the same thing to Shri Krishna and Shri Krishna agreed. Shri Krishna selected the Pandavas for this Yagya and ordered Yudhishthira to sit as the chief in this Yagya. After this Yudhishthira sat in the yagya and the yagya was completed. After the completion of the Yajna, peace was re-established in the world.
