Ever since the fall into sin the Lord had made clear that in some way a sacrifice had to be made to atone for or cover people’s sin (Genesis 3:21; consider also the sacrifices for sin God required at the tabernacle, Leviticus 1—5). But precisely whom these sacrifices foreshadowed and how he would go about atoning for sin was unclear to the prophets; this was detail that the Lord slowly revealed and ultimately did not make fully clear until Christ Jesus was sacrificed on the cross of Calvary as the Lamb of God. We might think here of a flower. When the plant comes out of the ground and begins its growth to maturity, the observer does not see what colour the flower will be. To satisfy his curiosity he might perhaps check his garden every day to see if there is any indication yet as to the colour that will pop out of the developing bud. If it is the first time he has encountered this plant, he may well be curious too as to what circumstances are needed to break the bud open so that it blooms. That is the sense of what the prophets of the Old Testament were so diligently seeking to learn: the circumstances of how God would bring about the fulfillment of the atonement foreshadowed since the beginning.
11 inquiring what person or time the Spirit of Christ in them was indicating when he predicted the sufferings of Christ and the subsequent glories.