N.J. Stat. § 40:3-2: Contracts as to bonds, notes not impaired

Nothing in this chapter shall be construed to require any sinking fund commission to do any act in violation of the contractual obligations of the municipality, county or school district, as the case may be, in respect to any bonds, notes or other evidences of indebtedness of such municipality, county or school district for the payment of which a sinking fund shall have been or may hereafter be created.