Children are innocent upto 12 years

Mahabharata Adiparva Sambhavaparva section 107-109
Sri Sadgurbhyoh namah

The third child born to Vyasa from a slave, is named Vidura. He is a virtuous person, intelligent, wise, and well versed in political science. He is actually God of justice (Yama) born due to a curse of Rishi Mandavya.

Janamejaya asked "What was the sin of Yama, that Rishi Mandavya cursed him for?".

Sage Vaisampayana recounts the story of Mandavya.

Mandavya muni : There was a muni by name Mandavya. He was sitting in his ashram undre a tree doing penance, and observing a vow of silence. A band of robbers were fleeing the royal gaurds with their loot. They hid in the ashram of Mandavya. Gaurds repeatedly asked Mandavya about the robbers. He didnt break his silence. They searched the premises and arrested the robbers and also the muni Mandavya and took him to the King.

The king has unjustly impaled him along with the robbers. The rishi Mandavya , though impaled and without food was alive for a long time due to his ascetic merit. He summoned other rishis, who came towards him as birds and animals. They asked him, for what sin he was impaled. Mandavya replied, "Who can I blame for this other than myself?".

King came to know about Mandavya's extraordinary powers and realised that he has made a mistake, asked pardon of muni. Mandavya forgives the king and the king tries to remove the ke from the body of Mandavya. since it was not possible, he cuts the outer part of the stake and leaves some part of the stake inside the body of Mandavya.

Muni Mandavya lives rest of his life with a small piece of stake inside his body and does great penance. He comes to be known with the name Ani-Mandavya (Mandavya with a stake within).

And one day Mandavya visited God of Justice Yama and enquired about the sin committed by Mandavya due to which he was made to suffer impalement on a stake.

Yama replies that once Mandavya has impaled a tiny insect on a blade of grass. Just as a small gift to someone increases religious merit manifold, a small sin will also multiply manifold and served to the same person.

Mandavya asks Yama "What age was I when I pierced the insect?". Yama says "You were a child when you did that act".

Mandavya then says "The scriptures will not consider the act of a child as sinful upto the age of 12. Since you acted unjustly and meted out a punishment to me disproporionate to the offence I caused, you shall be born on earth to a sudra woman. and from this day I am raising the limit of sinless age to 14."

My Commentary :

When other rishis asked Mandavya what sin he has committed, he replies "apart from myself who shall I blame". This tells us that what we sow we reap, law of karma and also what is coming is a prasada of god. Not everytime we get good things, one has to take responsibility.

This also tells the state of Muni Mandavya, he sees Self in all.

and when King asks for pardon, inspite of being impaled on a stake he forgives him.

Forgiveness is the greatest virtue.

Whereas he curses God of Justice. This is to establish dharma that a child is sinless upto the age of 14.

Peace

Prasad