Passover, Lent, Easter:1Corinthians 5:7–8 (ESV): Cleanse out the old leaven that you may be a new lump, as you really are unleavened. For Christ, our Passover lamb, has been sacrificed. 8 Let us therefore celebrate the festival, not with the old leaven, the leaven of malice and evil, but with the unleavened bread of sincerity and truth.

Matthew 15:17-27, Exodus 12:1-20, Romans 14:5, Ephesians 1:5, Matthew 4:1-11, ***Esther 4:16-another example of fasting being a preparatory.