Stepbystep guide on how to write contracts for leases, business partnerships, and employment contracts. Under Illinois law, an acceptance occurs if the party assented to the essential terms contained in the offer (Klein v.Klein, 2017 IL App (1st) 153393-U, ¶ 23. The answer lies in four critical ingredients: an offer, acceptance, consideration, and mutual intent to establish a legal commitment. In this video, we will go over everything you nee to know about Illinois real estate purchase agreements. This handbook guides attorneys through the process of creating, formatting, and modifying contracts. Illinois courts define a contract as 'an agreement between competent parties, upon a consideration sufficient in law, to do or not to do a particular thing'. The Parties to this contract are the State of Illinois acting through the undersigned Agency (collectively the State) and the Vendor. Illinois State Bar Association. Legal Requirements, Offer, acceptance, consideration are essential for contract validity.