Mahabharata Adi Parva Chapter 164:2

Mahabharata Adi Parva (Vaka-vadha Parva )

Mahabharata Adi Parva Chapter 164:2 There is no one on earth equal unto Bhima in might; he may even overcome that foremost of warriors, the holder of the thunderbolt himself. Soon after his birth he fell from my lap on the breast of the mountain. By the weight of his body the mass of stone on which he fell down broke in pieces. From this also, O son of Pandu, I have come to know Bhima's might. For this reason have I resolved to set him against the Brahmana's foe. I have not acted in this from foolishness or ignorance or from motive of gain. I have deliberately resolved to do this virtuous deed. By this act, O Yudhishthira, two objects will be accomplished; one is a requital of the services rendered by the Brahmana and the other is the acquisition of high religious merit. It is my conviction that the Kshatriya who rendereth help unto a Brahmana in anything acquireth regions of bliss hereafter. So also a Kshatriya who saveth the life of a Kshatriya achieveth that great fame in this world as in the other. A Kshatriya rendering help unto a Vaisya also on this earth certainly acquires world-wide popularity. One of the kingly tribe should protect even the Sudra who cometh to him for protection. If he doeth so, in his next life he receiveth his birth in a royal line, commanding prosperity and the respect of other kings. O scion of Puru's race, the illustrious Vyasa of wisdom acquired by hard ascetic toil told me so in bygone days. It is therefore, that I have resolved upon accomplishing this.'"