Kautilya's Arthashastra 3.1.16

3.1.16

paścimaṃ caiṣāṃ karaṇam ādeśādhivarjaṃ śraddheyam // iti vyavahārasthāpanā /

Such agreements with the exception of orders (Adesa=probably a bill of exchange) and hypothecations may be binding though entered into by a third person. Thus the determination of the forms of agreement.