I am really not sure where the idea that a spanking is necessary to purge a child of sin-guilt came from, but I cannot believe the number of Christian parenting books and resources that espouse this idea as though it is biblical! All that I can find in the Bible is that Jesus came to this earth to die in our place, taking our sin-punishment upon himself, suffering all the shame and pain caused by our sin, so that we WOULD NOT HAVE TO!! Now, doesn't it seem pretty hypocritical of Christian parents to spank their children for their children's sins, but then themselves be able to turn to a perfect Lamb when they sin? Why can't we point our children to Christ when they sin?? They need to learn that Jesus took care of all their guilt and shame, and before God they are forgiven.
I submit that a child who grows up being spanked as a means to relieve his/her guilt, will have a hard time accepting God's unconditional forgiveness when they are "too old" to be spanked. This child will feel that there is something else that they ought to do to make themselves right with God; they will feel that they ought to somehow make themselves suffer a bit to relieve their guilt. In fact, many Christian kids begin cutting themselves around their teenage years. I am personally acquainted with several who do. I asked one of these teens why they felt they needed to cut themselves. She explained to me that when she was feeling bad about herself, cutting relieved some of the bad feelings. Hmmm....
Recently, my husband was reading about Martin Luther, and the prevailing beliefs of his time. One of the main beliefs at this time had to do with penance. If you sinned, then you needed to do some sort of penance and God would then forgive you. Clearly, people were not encouraged to look only to Christ for forgiveness. Martin Luther would beat himself raw whenever he sinned, hoping to purge his guilt, hoping to punish himself, hoping to keep himself from sinning again. Many monks of old would treat their bodies severely. They did this in hopes that they would then stay away from sin and know God better. Did it work? Of course not!
Sin is nasty; and it has intrinsic consequences. I do not propose that we shield our children from experiencing these consequences. However, I do challenge the idea that a spanking relieves a child from sin-guilt. I think that parents who spank to relieve their child's guilt are missing a golden opportunity to point their children to the foot of the cross when they do wrong. Yes, the child may still experience some of the yuckiness of sin through logical consequences (not through punishment or shaming), but they will see Christ as their forgiveness; they will learn to practice walking in grace. They will not have a need to "do penance" by hurting or otherwise punishing themselves when they sin. They will learn to rely on Christ to give them the strength to do right the next time.