My dear, Its simple requirement from embassy to show that you are resident of KSA on valid documents and have traveled in and out side of the kingdom .
As you are a national of an other country but living in Kingdom, so these documents are the proof of your legal status here because you are applying for visa from within the Kingdom of Saudi Arabia .
For this purpose, they need your Iqama, ERE as a proof.
There is no need to mention that you will resign and get final exit once your visa is approved. Final exit has no meaning at this stage of your application.
All you need to do is, attach your current employment letter, giving detail of salary details, Salary slips of financial statement period, Resident Card (i.e. Iqama), ERE, Educational documents, SOP and other relevant documents in support of your application.
You can find further detail on below links:
http://www.cic.gc.ca/english/helpcentre/glossary.asp#instruction_guide
https://www.canada.ca/en/immigration-refugees-citizenship/corporate/contact-ircc/offices/international-visa-offices/riyadh.html
https://www.saudia.com/TRAVEL-WITH-SAUDIA/Where-we-fly/Visa-Information/Canada-Visa-Information?sv_lang=en&sv_cn=SA
https://www.saudia.com/saudiairlines2/Articles/Travel/visas info/canada/visitor guide.pdf
Riyadh Visa Office Instruction Guid;
http://www.cic.gc.ca/english/pdf/kits/forms/IMM5887E.pdf
Hope, it will help you out for your visa application.