Sub Comments_AddResponsesToAll_6() ' 08/10/2020
  ' Loops through all comments and appends text from Excel to beginning of the comment.
  Dim rngComment As Range, lngCommentNum As Long, arrExcelData As Variant
  
  arrExcelData = GetExcelData   'get the excel data once and store in an array for reuse
   
  For lngCommentNum = 1 To (ActiveDocument.Comments.Count)
    Set rngComment = ActiveDocument.Comments(lngCommentNum).Range
    rngComment.InsertBefore arrExcelData(lngCommentNum, 14) & vbCr
  Next
  
End Sub

Function GetExcelData() As Variant
    Dim myWB As Excel.Workbook
    Dim objExcel As New Excel.Application
    Set myWB = objExcel.Workbooks.Open("C:\Temp\TestFile.xlsx")
    GetExcelData = myWB.sheets(1).UsedRange.Value
    myWB.Close
    Set myWB = Nothing
    Set objExcel = Nothing
End Function