Mbh 3.36.2a

“O thou of mighty arms, it is even so as thou hast said. But, O thou foremost of speakers, listen now to another word I say. Whatever sinful deeds, O Bhima, one seeketh to achieve, depending on his courage alone, become always a source of pain. But, O thou of mighty arms, whatever is begun with deliberation, with well-directed prowess, with all appliances, and much previous thought, is seen to succeed. The gods themselves favour such designs. Hear from me something about what, proud of thy might, O Bhima, and led away by thy restlessness, thou thinkest should be immediately begun. Bhurisravas, Sala, the mighty Jarasandha, Bhishma, Drona, Karna, the mighty son of Drona, Dhritarashtra’s sons--Duryodhana and others--so difficult of being vanquished, are all accomplished in arms and ever ready for battle with us. Those kings and chiefs of the earth also who have been injured by us, have all adopted the side of the Kauravas, and are bound by ties of affection to them. O Bharata, they are engaged in seeking the good of Duryodhana and not of us. With full treasures and aided by large forces, they will certainly strive their best in battle. All the officers also of the Kuru army together with their sons and relatives, have been honoured by Duryodhana with wealth and luxuries. Those heroes are also much regarded by Duryodhana. This is my certain conclusion that they will sacrifice their lives for Duryodhana in battle. Although the behaviour of Bhishma, Drona, and the illustrious Kripa, is the same towards us as towards them, yet, O thou of mighty arms, this is my certain conclusion that in order to pay off the royal favours they enjoy, they will throw their very lives, than which there is nothing dearer, in battle. All of them are masters of celestial weapons, and devoted to the practice of virtue. I think they are incapable of being vanquished even by gods led by Vasava himself.