Although the application package does not specify it, I sent the bank statement just in case. I think that schedule 4 is a sworn declaration, and that is enough.
The application guide states:
Question 4, Funds:
Indicate the amount of unencumbered (by debts or obligations) transferable and available funds you have in Canadian dollars.
Read the declaration carefully. Sign and date in the boxes provided. By signing, you declare that you fully understand the questions asked, and that the information you have provided is complete, truthful, and correct.
It doesn't mention to submit proof of fund.