Vincent's NT Word Studies
38. Him (touton). Lit., that one. It marks him very strongly, and is an emphatic position at the end of the sentence.Departed (apostanta). Rev., withdrew. It furnishes the derivation of our word apostatize.
Robertson's NT Word Studies
15:38 {But Paul thought not good to take with them} (paulos de exiou--me sunparalambanein touton). The Greek is far more effective than this English rendering. It is the imperfect active of axiow, old verb to think meet or right and the present active infinitive of the same verb (sunparalambanw) with negative used with this infinitive. Literally, "But Paul kept on deeming it wise not to be taking along with them this one." Barnabas looked on it as a simple punctiliar proposal (aorist infinitive), but Paul felt a lively realization of the problem of having a quitter on his hands (present infinitive). Each was insistent in his position (two imperfects). Paul had a definite reason for his view describing John Mark as "him who withdrew from them from Pamphylia" (ton apostanta ap' autwn apo pamfulias). Second aorist active articular participle of afistemi, intransitive use, "the one who stood off from, apostatized from" (our very word "apostasy"). And also as the one who "went not with them to the work" (kai me sunelqonta autois eis to ergon). At Perga Mark had faced the same task that Paul and Barnabas did, but he flinched and flickered and quit. Paul declined to repeat the experiment with Mark.