Using variable in Application.Index

Hello. Hopefully this is an easy question to answer. I am attempting to write the results of an index function performed on an array to another array. I am using the following:

Sub testRmvDupe()

    Dim wsUn As Worksheet
    Set wsUn = Sheet1
    Dim unLastRow As Long
    Dim rngUn As Range
    Dim arrUn As Variant
    Dim var As Variant
    Dim unRowsStr As String
    Dim test As Integer
    test = 10
    
      
        With wsUn
            unLastRow = .Range("a1").CurrentRegion.Rows.Count
            arrUn = .Range("a2", .Range("i" & unLastRow))
            var = Application.Index(arrUn, [row(1:10)], Array(2, 1))
        End With

End Sub

works as expected. If instead, I substitute the "test" variable for "10" in "[row(1:10)]," I receive Error 2015. Is there a way to use a variable in place of a constant here? I am trying to write certain columns to the array, and the number of rows changes constantly.

Thanks,

Mayday