A defending player can block only with creatures they control. Those creatures can block only creatures attacking that player, a planeswalker that player controls, or a battle that player protects.
April 27, 2018 · Dominaria
A defending player can block only with creatures they control. Those creatures can block only creatures attacking that player or a planeswalker that player controls.
September 30, 2011 · Innistrad
A defending player can block only with creatures he or she controls. Those creatures can block only creatures attacking that player or a planeswalker that player controls.
June 17, 2011 · Commander 2011
A defending player can block only with creatures he or she controls. Those creatures can
February 4, 2011 · Mirrodin Besieged
A defending player can block only with creatures he or she controls. Those creatures can block only creatures attacking that player or a planeswalker that player controls.
October 1, 2010 · Scars of Mirrodin
A defending player can block only with creatures he or she controls. Those creatures can
February 1, 2010 · Worldwake
A defending player can block only with creatures he or she controls. Those creatures can block only creatures attacking that player or a planeswalker that player controls.