In an action involving competing claims of lien priority between the defendant-seller of real property, which took back a security interest on property sold to a developer, and the plaintiff-bank which financed development of the project through a construction loan, judgment in favor of defendant-seller is affirmed, where: 1) defendant-seller's agreement to subordinate its security interest to that of the bank is unenforceable where the developer and the plaintiff-bank entered into a side agreement between themselves, to which the defendant-seller did not consent, about which it knew nothing, and which substantially impaired its security; and 2) defendant-seller's lien therefore has priority.