Function To Return Common Words To 2 Cells

I'm trying to write UDF which getting RegEx pattern and a certain cell as arguments and returns only matching string. For examples for string "The quick brown fox jumps over the lazy dog", and RegEx pattern "w{4}" the function will return two words "OVER" and "LAZY". What should I change in my code?

Function GetPattern(myPattern As String, myString As String)
Dim regEx As RegExp
Dim Matches As Object
Set regEx = CreateObject("VBScript.RegExp")

With regEx
.Pattern = myPattern
.IgnoreCase = True
End With
GetPattern = regEx.Replace(myString, "$1")
End Function