President Thomas S. Monson mentions worthiness multiple times in his October 2011 Priesthood Conference talk:
What a wonderful gift we have been given—to hold the priesthood, which is “inseparably connected with the powers of heaven.” This precious gift, however, brings with it not only special blessings but also solemn responsibilities. We must conduct our lives so that we are ever worthy of the priesthood we bear. We live in a time when we are surrounded by much that is intended to entice us into paths which may lead to our destruction. To avoid such paths requires determination and courage.
Ours is the responsibility to be worthy of all the glorious blessings our Father in Heaven has in store for us. Wherever we go, our priesthood goes with us. Are we standing in holy places? Please, before you put yourself and your priesthood in jeopardy by venturing into places or participating in activities which are not worthy of you or of that priesthood, pause to consider the consequences. Each of us has had conferred upon him the Aaronic Priesthood. In the process, each received the power which holds the keys to the ministering of angels. Said President Gordon B. Hinckley:
“You cannot afford to do anything that would place a curtain between you and the ministering of angels in your behalf.
“You cannot be immoral in any sense. You cannot be dishonest. You cannot cheat or lie. You cannot take the name of God in vain or use filthy language and still have the right to the ministering of angels.”
Many of you brethren have served as missionaries throughout the world. Many of you young men will yet serve. Prepare yourselves now for that opportunity. Make certain you are worthy to serve.
With all my heart and soul, I pray that every man who holds the priesthood will honor that priesthood and be true to the trust which was conveyed when it was conferred. May each of us who holds the priesthood of God know what he believes. May we ever be courageous and prepared to stand for what we believe, and if we must stand alone in the process, may we do so courageously, strengthened by the knowledge that in reality we are never alone when we stand with our Father in Heaven.
As we contemplate the great gift we have been given—“the rights of the priesthood … inseparably connected with the powers of heaven”—may our determination ever be to guard and defend it and to be worthy of its great promises.
Thomas S. Monson, “Dare to Stand Alone,” October 2011.