I cannot test your macro as I do not have the HebrewDate worksheet function.

Assuming you have that function, you may have put  the macro in the wrong
place. It must be in a module rather than in a worksheet or workbook object.
Only modules publish their functions so they can be used in the worksheet.

Yea i did it threw a module.. i checked if the function  is working
first by using numbers and not string, i did a simple check and the
function worked. but when is summoned the hebrewdate function from
the worksheet is started having problems.
is there a way in visual  basics to see the steps the function does?
so i can trace the problem?

You can set a breakpoint in the function  by clicking in the left margin. It
appears as brown dot and the macro is supposed to stop when it gets there.
When this happens you can put  the mouse cursor on the name of any variable and
its value appears as a pop-up. You then step the through the macro with f8.

Rather than call the macro from the spreadsheet you can enter a command in the
immediate window (lower right in the editor) and it will start the macro.