Lewis & Short

ob-testor, ātus, 1, v. dep., to call as a witness to any thing; to protest or assert by a person or thing (syn.: testor, obsecro, supplico; class.).

  1. I. In gen.: necessitudinem nostram tuamque in me benevolentiam obtestans, Cic. ad Brut. 1, 13, 1: deūm hominumque fidem, Liv. 2, 10: sacra regni, deos et hospitales mensas, Tac. A. 2, 65: summam rempublicam agi obtestans, id. ib. 12, 5: aut militum se manibus aut suis moriturum obtestans, id. H. 3, 10; Suet. Calig. 15 fin.
  2. II. Transf., to conjure by calling to witness; to entreat, beseech, supplicate, implore: per ego haec genua te, Plaut. Rud. 3, 2, 13; id. Aul. 4, 9, 4: per omnes deos te obtestor, ut, etc., Cic. Att. 11, 2, 2; Verg. A. 9, 260: vos judices, Cic. Cael. 32, 78: vos obtestor atque obsecro, ut, etc., id. Sest. 69, 147: id sibi ne eripiatis, vos obtestatur, id. Sull. 32, 89: obsistens obtestansque deum et hominum fidem testabatur, nequiquam eos fugere, Liv. 2, 10, 3.
    With double acc.: illud tePro Latio obtestor, ne, etc., Verg. A. 12, 819.
    Part.: obtestātus, a, um, in the pass. signif., earnestly entreated, supplicated, implored: obtestatus prece impensā, Amm. 31, 9, 4: obtestatā fide, App. M. 2, p. 125, 11.