In preparation for this special time with God, I urge you to examine your heart through prayer, and ask the Holy Spirit to reveal any unconfessed sin. Scripture records that God always requires His people to repent of their sins before He will hear their prayers. King David said:
Come and listen, all you who fear God, and I will tell you what he did for me. For I cried out to him for help, praising him as I spoke. If I had not confessed the sin in my heart, the Lord would not have listened. But God did listen! He paid attention to my prayer.
Praise God, who did not ignore my prayer or withdraw his unfailing love from me.
(Psalm 66:16-20, New Living Translation)
In your prayers, confess not only the obvious sins that come to mind, but allow yourself to linger in His presence, giving Him time to show you the less obvious ones as well. You may want to ask God if you are experiencing any of these signs of leaving your first love: worldly-mindedness, self-centeredness, spiritual indifference, unwillingness to share your faith in Christ with others, not spending sufficient time in God's Word and in prayer, a poor relationship with your spouse, your children, your friends, or other members of your church community.
Another great way to prepare for your fast is to practice what I call “spiritual breathing.” The concept is simple, but it has changed my own life and that of countless others.
Like physical breathing, spiritual breathing is a process of exhaling the impure and inhaling the pure. If you knowingly sin, breathe spiritually to restore the fullness of God's Holy Spirit in your life. You exhale by confessing your sins when you become aware of them, and you inhale by inviting the Holy Spirit to re-take control of your life. As an act of faith, trust Him to empower you. During the fast, spiritual breathing-constant reliance on the Holy Spirit-will enable you to resist temptation, not only to sin but to abandon your fast.
Although fasting is primarily a spiritual discipline, it begins in the physical realm. You should not fast without specific physical preparation.
If you plan on fasting for several days, you will find it helpful to begin by eating smaller meals before you abstain altogether. Resist the urge to have that “last big feast” before the fast. Cutting down on your meals a few days before you begin the fast will signal your mind, stomach and appetite that less food is acceptable.
Some health professionals suggest eating only raw foods for two days before starting a fast. I also recommend weaning yourself off caffeine and sugar products to ease your initial hunger or discomfort at the early stages of your fast.