The Arab states (including Lebanon) that invaded Israel in 1948 were just "defending their borders" (while they managed to seize the W. Bank and Gaza for themselves, blocking a Palestinian state)? Your theory of the purpose of possessing weapons is at best naive, and more to the point, idiotic. Iran does not need long-range missiles and nuclear weapons and 40,000 rockets placed in Lebanon on Israel's border to "defend its borders" from an Israel 1200 miles away. Its intention is to attack - FAR from its borders.
ISIS kills 22 in Yemen's Sanaa, Aden; targets both gov't and Houthi rebels (Reuters)