What personal characteristics motivates sir Bedivere to disobey king Arthur's order to throw the sword in the lake?

The personal characteristics might be greed or covetousness, or just thrift.

Sir Bedevere defies Arthur's orders the first 2 times he tells him to throw it away as he thinks that it would be a waste to throw such a powerful, useful weapon away as in many versions of the tale it had much power, and in some versions they said that if you fought with it, you'd never lose. However on the third time Arthur commands him to do so, Sir Bedevere can see he's intent on having it thrown in the lake and so does it. Also, he can see that Arthur will not be fooled into believing Sir Bedevere did it when he did not.