Popup message showing adjacent cell value when user enters value in cell

I am trying to generate a message to the user as follows:

Each time a value is entered in any cell in range W8:W140 (e.g W10), and the row (row 10) has a value in column G (cell G10)
then a msgbox will popup with the value of the cell in column G (cell G10)

Is this possible?

Try this:

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Both solutions are working when I enter a value. many thanks!
the problem is when I select a cell in column W and hit the delete button to clear the value, I get a Run Time Error '1004' Application-defined or object defined error on the msgbox line