Data Validation Error Message

[BillCPA]

Is there any way to use a cell address in the error message displayed with
data validation.

Example: cell A1=1 and A2=16, and data to be entered in cell C4 must be
equal to whatever is in A1 or A2. I can use a formula to check the value,
but when I display the error message, can I use A1 or A2 in the message, so
that it reads something like "This value must be equal to 1 or 16".

 

[Max]

An alternative alert is to use this in an adjacent cell eg in D4:
=IF(ISNA(MATCH(C4,A1:A2,0)),"This value must be equal to "&A1&" or "&A2,"")