These verses also contain instructions for the yearly celebration of the Day of Atonement. The fact that the Israelites repeated it year by year points to the incompleteness of the atonement that animal sacrifices made (cf. Heb. 9:7-12).
All the Israelites were to humble their souls (fast) and refrain from work in preparation for this event. This self-affliction included spiritual humbling as well as going without food (cf. Isa. 58:3). Fasting was an indication that the practitioner regarded his need to seek God as more pressing than his need to feed his body. It often accompanied prayer (cf. Ps. 35:13). Refraining from work resulted from the same sense of priority. No human activity was necessary nor did God permit it in addition to the sacrifice that He provided to atone for sin.
The promise of God in verse 30 is one that the Israelite was to believe and by which he could enjoy assurance of his fellowship with God. It is very clear from this verse and similar statements (cf. vv. 16, 22) that God promised forgiveness and cleansing to all who trusted in the efficacy of the sacrifices that He provided and prescribed.181
The writer of the Book of Hebrews saw the Day of Atonement as prefiguring Jesus' crucifixion (Heb. 9). Though the Day of Atonement is not something Christians observe, we can learn the nature of sin, the need for atonement, and the superiority of Christ's sacrifice by reflecting on this Jewish ritual in the light of Calvary (cf. Heb. 10:22-25).
