3 Indeed, from the very beginning of Our apostolic ministry, We have omitted no effort to further the cause of peace in the world through prayers, entreaties and exhortations. As you well remember, last year We flew to North America to speak about the most desirable blessing of peace at the General Assembly of the United Nations, before a very distinguished audience representing almost every nation. (2) We warned against allowing some to be inferior to others, and against allowing some to attack others. Instead, all should devote their efforts and zeal to the establishment of peace. Even afterwards, moved by apostolic concern, We did not stop urging those upon whom this great matter depends to ward off from mankind the frightful disaster that might result.
Source: Christi Matri (Vatican.va)