Recognize Text Values As Variable Names

I want VBA to take an equation that has been entered into an worksheet cell as text and evaluate it. Here's a very simplified example that shows the concept:

Cell A1 may contain the text: "A * B + C"

I would like to do something on the order of this in VBA:

Sub Test()
Dim A As Integer, B As Integer, C As Integer

A = 2
B = 4
C = 6

MsgBox Evaluate(Workbooks("Book1").Sheets("Sheet1").Range("A1").Value)

End Sub

Obviously, this doesn't work, but I want it to show a result of 14. The actual situation is much more complex, but it all comes down to being able to evaluate the text in a worksheet and recognize the variable names that are in it.