Beat your plowshares into swords
and your pruning hooks into spears.
Let the weakling say,
"I am strong!"
- Joel 3:10

Or as Jesus said:

He said to them, "But now if you have a purse, take it, and also a bag; and if you don't have a sword, sell your cloak and buy one.
- Luke 22:36

In other words, it’s better to be armed and cold without a coat, than to be comfortable and defenseless.