Malala's comments came during an address to the U.N. Youth Assembly, a gathering of more than 500 international youth leaders, the U.N. News Center reported.
"Let us pick up our books and our pens. They are our most powerful weapons. One teacher, one book, one pen, can change the world," Malala said. "The extremists were, and they are, afraid of books and pens. The power of education frightens them. They are afraid of women."
Friday, Malala's 16th birthday, was declared "Malala Day" by U.N. Secretary-General Ban Ki-moon, CNN reported.
Ban said that on Malala's "special day, she's calling on us [to keep] our promises -- investing in young people and [putting] education first."
Malala was shot in the head by a Taliban gunman in October. She was targeted because she supported the right of girls to attend school in Pakistan.
The teenager also presented Ban with a petition seeking education for all children, Voice of America reported. As of Thursday, Malala's petition had more than 330,000 signatures. The petition calls on the U.N. General Assembly to provide money for new teachers, schools and books, and to recommit to getting all children into the classroom by December 2015.
Martin Nesirky, Ban's spokesman, said the secretary-general looked forward to welcoming the teen to the United Nations and declared Friday as "Malala Day."
"From the day that terrible shooting -- assassination attempt -- took place, Malala Yousufzai is a symbol for the rights of girls, and indeed the rights of all young people, to an education. And she has further underscored that symbolism through her remarkable recovery and her eloquence in explaining her case and her position," Nesirky said.