options explicit error

Options explicit Error, i am getting this invalid procedure error with the below code. can some experts here tell me why? i declared all my variables already. I'm using excel 2013.

Options Explicit

Sub test123()
    Dim wb As Workbook: Set wb = ThisWorkbook
    Dim x As Integer

            For x = 1 To 10


            Next x
End Sub

OMG thank you so much!