Multiple selectors not working

Multiple selectors not working

Trying to do something like this, but nothing ever shows. I have several "Smith"'s (Adam, Bill and Cathy) as test data...

// Hide everything first to start fresh...
$(".user").hide();

// This does not show anything...I expect the TR's that contain "Adam Smith" and "Bill Smith" in the
// TD's whose id's start with "firstName" and "lastName" respectfully to be shown...but alas, nothing:
$(".user").children("TD[id^=lastName]:contains(Smith):TD[id^=firstName]:contains(a)")
                        .parent()
                        .show();

Any thoughts?