Probably for the dative case of G3588; an enclitic particle of asseveration by way of contrast; insooth: - [used only with other particles in {compounds} as {G2544} {G3305} {G5105} {G5106} etc.]
Heb 12:1WhereforeG5105 seeing we also are compassed about with so great a cloud of witnesses, let us lay aside every weight, and the sin which doth so easily beset us, and let us run with patience the race that is set before us,