"O Yahya, take the Scripture with power," meaning: with diligence and perseverance. "And We gave him judgment while still a child," meaning: understanding and intellect.
Yahya [bin Abi Kathir] said: It has reached us that when he was young, the children would say to him, 'O Yahya, come let us play.' And he would reply, 'We were not created for play!'