We see that the disciples received the Holy Spirit from Jesus when He appeared to them, and that they were baptized into the body of Christ "by" and "with" the Holy Spirit. This is accomplished by the blood of Christ at Calvary. But to understand it from the perspective of the feasts of the Lord, we must understand the meaning of the blood of the lamb killed at Passover as a type of the blood of Christ. "We have redemption through his blood (Ephesians 1:7)." Jesus "hath purchased [us] with his own blood (Acts 20:28)."

The children of Israel were told by God, "And the blood shall be to you for a token upon the houses where ye are: and when I see the blood, I will pass over you, and the plague shall not be upon you to destroy you (Exodus 21:13)." In Egypt when the Lord passed over the houses with the blood over the door, He "sealed" or "protected" the people within from the plague. Without this protection "every open vessel, which hath no covering bound upon it, is unclean (Numbers 19:15)."

This is why the celebration of Passover requires that "there be no leaven found in [the] houses (Exodus 12:19)." Leaven is a type of sin, and our "sins are forgiven (1 John 2:12)." Therefore, since no leaven is "in our house" because we are "clean through the word which [Jesus has] spoken unto [us] (John 15:3)", we are protected by the "seal" or "covering" of the Holy Spirit at redemption.