I understand, but original sin falls under the doctrines of reconciliation, which were Paul's to give. Trying to find it in the words of Christ would be very difficult. Truly, the whole chapter of Romans 5 sets this up quite nicely. However, I do see what you are trying to accomplish. The interpretion (by man) of Scripture can by twisted by preconcieved notions. That is why there is Biblical theology, Church tradition Theology, Systematic theology, etc. I don't use the theology of Church tradition, rather, I edge between Biblical and Systematic. Sometimes, however, a doctrine like "original sin" fits nicely with what I get from Scripture.