I want to use the Lookup function to reference cell values, not just
hand-entered values.

For example:
Column A Column B
1 23
2 45
3 65
4 78
5 93

I then want to enter a value into cell A9 and have a lookup function in cell
B9 that looks like this:
=LOOKUP(A9,{A1,A2,A3,A4,A5},{B1,B2,B3,B4,B5})

The lookup function works by entering in the corresponding values by hand
into the cell:
=LOOKUP(A9,{1,2,3,4,5},{23,45,65,78,93})

But that's not what I need! I appreciate any help.