how to compare value from list with VBA?

[jaik22]

I am trying to make code that compare value from the list. in column AB there will be list of the values.
So if user put values from AB column between F20 and last row of F, 000 value should be in the I column
If that values in the AB list and not I column is matching 000 I want to give warning message and end the code.

    With Sheets("testing")
        eFilters = .Range("AB1", .Cells(.Rows.Count, "I").End(xlUp)).Value

I Kinda get the starting part, but can't figure it out to compare f20 to last row and I20 to last row.
Can anyone give me any advice?

Thank you!