The sermon explores the significance of the Passover, emphasizing its role as a memorial of deliverance from Egypt and a foreshadowing of Christ's sacrifice. It highlights the importance of remembering God's actions, partaking of His grace through substitutionary atonement, and continually repenting of sin, drawing parallels between the Old Testament festival and the New Testament Lord's Supper. The passage underscores the necessity of purity and truth, urging believers to actively mortify sin and embrace the covenant relationship with God through remembrance, participation, and repentance, ultimately finding assurance of salvation through Christ's atoning work.