help please with matching cells in a LOOP

[shabbyporpoise]

Hello Forum
I am trying to loop through a doc. I want to test/match every item in the column against the first item, then loop and then test/match every item against the second item...and so on... and so on. I can successfully go through one column all the way to the end testing every item against the first item but when I get to the end of the list I get a run-time error 9 "subscript out of range" What am I missing?

Sub testArray()
   
   Dim rules(1 To 10000, 1 To 6) As String
   Dim intRow As Integer, intColumn As Integer, num As Integer
   Dim i As Integer, a As Integer, x As Integer
   
   num = InputBox("how many?")
   i = 1
   a = 1
   x = 1
   
   For intRow = 1 To num
   For intColumn = 1 To 6
        rules(intRow, intColumn) = Cells(intRow, intColumn).Value
     
    Next intColumn
    Next intRow
    
    For x = 2 To num
        For i = 2 To num
        
                If rules(i, 3) = rules(i - a, 3) Then '(error occurring here)
                    MsgBox "found a match"
                   
                 Else
                    MsgBox rules(i, 3) & " no match  " & rules(i - a, 3)
            
                End If
                a = a + 1
        Next i
        i = i + 1
    Next x
    
End Sub