I second the links already given and also: http://parentingfreedom.com/discipline/
A little down on the page it talks about the word for "child" in hebrew;
|In three of the rod verses in Proverbs, the English word we see is “child”, but the original Hebrew word is na’ar. It means the “one shook lose” and definitely refers to the young adult or teenage years. None of the words translated as “child/children” in the book of Proverbs actually refer to those under the age of ten or twelve. This is significant! The rod verses are NOT directed toward little children.
I also think the bible is rife with verses that go against punitive punishment and if debating with other Christians I use these:
"the fruit of the Spirit is love, joy, peace, longsuffering, gentleness, goodness, faith, Meekness, temperance. . . " (Gal. 5:22, 23b),
"Love is patient, love is kind" ( I Cor. 13 )
". . . we proved to be gentle among you as a nursing mother tenderly cares for her own children" (I Thess. 2:7)
"do to others what you would have them do to you" (Mat. 7:12), etc.
My favorite is Matthew 25: 41-46;
"'Depart from me, you who are cursed, into the eternal fire prepared for the devil and his angels. For I was hungry and you gave me nothing to eat, I was thirsty and you gave me nothing to drink, I was a stranger and you did not invite me in, I needed clothes and you did not clothe me, I was sick and in prison and you did not look after me.' They also will answer, 'Lord, when did we see you hungry or thirsty or a stranger or needing clothes or sick or in prison, and did not help you?' He will reply, 'I tell you the truth, whatever you did not do for one of the least of these, you did not do for me.'" (Mat 25: 41-46)