Breaking Bad, Season 4

Lawson:
You know, mister, I've been providin' my services for the past thirty-odd years. You'd think in that time I'd learn better than to ask a man his business. Especially not one referred by the lawyer. But I feel the urge to ask you, we strictly talking defense here?

Walter:
Yes. Absolutely, defense. Why?

Lawson:
'Cause if it's just personal protection, aside from a bucket of money, you'd save yourself a potential felony two-spot for carrying a weapon with a defaced serial number if you'd just buy it legally.

Walter:
Yeah, but... if you did have to use it, wouldn't it still be better to use one that couldn't be traced?

Lawson:
This is the west, boss. New Mexico's not a 'retreat' jurisdiction. A man steps to you intent on doing bodily harm, you got every right to plant your feet and shoot to kill. Some call it a moral right and I do include myself within that class. All this to say, I'm happy to take your money, but if you're not a convicted felon, you might best be advised to bear your arms within the confines of the law.

Walter:
It's for defense. [beat] Defense. I'll take it.