To be careless is to be reckless. We are to be wise about our safety (WSNT note on Mt 10:16). As he was getting ready for the WWII Battle of Midway, Japanese Admiral Nagumo was careless. He was so confident that he just ordered a very minimal reconnaissance. Had he been more thorough, he would have known the Americans had two aircraft carriers within striking distance and it would have changed the outcome of the battle. Similarly, in the American Revolutionary War, British Major General James Grey led his troops into an American camp which was carelessly asleep, having failed to post sentries. Three hundred Americans were killed or wounded by bayonet with another hundred captured. It was known as the Paoli Massacre (Middlekauff, The Glorious Cause, p 389). Finally, during the winter of 1690 a couple hundred French and Indians left Montreal to attack Albany. Albany, being warned, told the people at their outpost in Schenectady to be alert. Since the weather was so bad, the people at Schenectady assumed they wouldn’t be attacked. Instead of being on guard (Prov 28:14, NAB), they left the gate open with two snowmen as sentries. The French and Indians slaughtered everyone in the town (Leckie, The Wars of America, p 17-18).
Carelessness can be very costly (Prov 27:12, Berkeley). Jesus said we should be alert and praying (Lk 21:36). It is easy to be deceived because Satan has great deceptive abilities (Rev 12:9). Sometimes, like Nagumo, we just aren’t as thorough as we know we should be (Heb 6:12, JB). At other times, we are just plain lazy as the Americans were at the Paoli Massacre. Finally, we can be careless by ignoring advice and making stupid assumptions as was true at Schenectady. Let us learn from these examples and obey the command of Jesus Christ to be alert.
Instead of being timid, learn to be appropriately bold.