The blood flowed into a basin, and the attendants brought a branch of hyssop, which Jesus dipped in it.
Then he went to the door of the room, stained the sideposts and the lock with blood, and placed the branch which had been dipped in blood above the door.

He then spoke to the disciples, and told them, among other things, that the exterminating angel would pass by, that they would adore in that room without fear or anxiety, when he, the true Paschal Lamb, should have been immolated--that a new epoch and a new sacrifice were about to begin, which would last to the end of the world.
They then went to the other side of the room, near the hearth where the Ark of the Covenant had formerly stood.

Fire had already been lighted there, and Jesus poured some blood upon the hearth, consecrating it as an altar; and the remainder of the blood and the fat were thrown on the fire beneath the altar, after which Jesus, followed by his Apostles, walked round the supper-room, singing some psalms, and consecrating it as a new Temple.

The doors were all closed during this time.

Meanwhile the son of Simeon had completed the preparation of the lamb.