Sacrifice starts

Yudhistira bowed down before  Bhishma ,Drona ,Kripa , Aswatthama and Duryyodhana and asked for their blessings.
 He appointed Dussasana to oversee the department of food . Aswatthama was asked to attend on the Brahmanas. Sanjaya was appointed to offer return gifts to  the invited kings. Bhishma and Drona looked over to see if everything going as per procedure. Duryyodhana was in charge of collecting the gifts brought by the invited kings. Krishna went about welcoming the Brahamans.

Bhishma asked Yudhistira to ensure that the invited guests was treated with respect and all were given offerings from the sacrifice. Yudhistira asked Bhishma who should be the first to receive the offerings. Bhishma said Krishna deserved this and he should be treated as the supreme and be worshipped.
As the sun is the most brilliant among all, so is Krishna, Bhishma said. The sacrifice is illuminated by his presence.
Thus commanded by Bhishma, Yudhistira and Bhisma both worshiped Krishna. The king of Chedi, Sisupala did not like this.

He said Krishna did not deserve this respect. Bhishma who was not even a king, had no right to suggest names of who deserved this respect. If some one had to respected, it should be Krishna's  O bull of the Kuru race, if thou regardest Krishna as the oldest in age, here is Vasudeva, and how can his son be said so in his presence? Or, if thou regardest Vasudeva father, Vasudeva, who was elder to Krishna in age and wisdom. There were other warriors like Drupada who could be respected. So, why Krishna? There were warriors like Drona and Kripa who deserved this and not Krishna.
Krishna was not a priest . By worshiping Krishna, the other mighty kings were being insulted.

Having said this, Sisupala walked out of the assembly hall. Yudhistira tried to get back Sisupala. He ran after him and said Bhisma knew Krishna better than others and there would be a reason why he had chosen him.
Sisupala then started asking the assembled kings to support him.  Approaching Bhisma, Yudhistira wanted to know how to tackle this situation. Bhishma asked him not to worry. The dogs would bark but they would be able to harm a lion.

Sisupala said Bhishma was old and did not know what he was saying. Krishna had slain all who were weak. He slew Kamsa who was his relative. He said Bhishma's celebacy was from ignorance and not for any virtue.
Continuing, he said there was once an old swan who always spoke of morality. Other birds would leave their eggs with him to watch over. This bird, seeing the other birds had gone, would eat up the eggs. When the other birds saw this, they attacked and killed the swan. Bhishma was like this swan.

Bhima was enraged to hear these words of Sisupala. Bhishma then tried to pacify Bhima.