Lock Fields on Validation?

I want to have 2 text fields lock but only after a correct validation of proper initials from an individual. I have a script to lock fields and s script to validate. How do I put the two together?

Validate:

event.rc = true;

if (event.value != "" && event.value != "AAAA" && event.value != "BBBB")

{

    app.alert("The entered value needs to be either 'AAAA' or 'BBBB'!");

    event.rc = false;

}

Lock:

var fieldsToLock = ["TimeField309", "TimeField317"];

for (var i in fieldsToLock) this.getField(fieldsToLock)

How do I put these 2 together for the proper result I'm looking for?