Can I verify field to external list so that the system can validate if the entry is a valid code/number?

I need to have a spot on my form that verifies that the numbers entered on the form match a set certain set of numbers.  For example, I have a list of "membership card" numbers.  The members go online to fill out their information to attach their info the their membership card.  I want the system to validate that the membership card number they enter is actually a card number.