"malice and wickedness; but with the unleavened bread of sincerity and truth.” 1 Corinthians 5:7, 8 . PP 278.1"
"Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth."
EGW directly quotes 1 Corinthians 5:8, making this an explicit allusion.
"Seven days shall ye eat unleavened bread; even the first day ye shall put away leaven out of your houses: for whosoever eateth leavened bread from the first day until the seventh day, that soul shall be cut off from Israel."
Both passages discuss the importance of unleavened bread and removing leaven, symbolizing purity and the removal of sin. While EGW directly quotes 1 Corinthians 5:7,8, the underlying theme connects to the Exodus passage.
"Before obtaining freedom, the bondmen must show their faith in the great deliverance about to be accomplished. The token of blood must be placed upon their houses, and they must separate themselves and their families from the Egyptians, and gather within their own dwellings. Had the Israelites disregarded in any particular the directions given them, had they neglected to separate their children from the Egyptians, had they slain the lamb, but failed to strike the doorpost with blood, or had any gone out of their houses, they would not have been secure. They might have honestly believed that they had done all that was necessary, but their sincerity would not have saved them. All who failed to heed the Lord's directions would lose their first-born by the hand of the destroyer. PP 278.2"
"And ye shall take a bunch of hyssop, and dip it in the blood that is in the bason, and strike the lintel and the two side posts with the blood that is in the bason; and none of you shall go out at the door of his house until the morning."
The EGW passage directly interprets and expands upon the instructions in Exodus 12:22, emphasizing the importance of obedience to God's specific commands for protection. The connection is clear and based on a direct reading of the biblical text.