Bill1940 is correct, i.e., no Pope can alter or rewrite or make Sacred Scripture null and void, as in the case of this particular issue, and there is clearly a significant set of Scriptural references, as well as citations from Sacred Tradition and Saints, all of which speak to the contrary of recent comments. When Pope Francis makes such noted statements, he is merely giving his personal opinion, not to be confused with establishing some universal new truth in an infallible declaration. It’s often been the case with this Successor of Peter that his words have given rise to much confusion, especially about this and other long-held traditional issues making the news. I recently read a good article that covers several aspects of this topic:
onepeterfive.com/getting-it-wrong-about-the-death-penalty/
Personally, I’ll continue to hold on to what Sacred Scripture, Sacred Tradition, and the Saints have addressed in regard to capital punishment. I will always respect and listen to Pope Francis, but he has absolutely no authority to trump God’s Word merely because he feels it conflicts with his sentiment. He has a right to personal opinions, but it would be best if he spoke with more prudence in accordance with what is clearly established in Sacred Scripture and Sacred Tradition. Dei Verbum II 10