{That thy faith fail not} (hina m(8820)eklip(8869) he pistis
mou). Second aorist active subjunctive of purpose with hina
after ede(8874)h(886e) ({I prayed}) of ekleip(935c), old verb. Our word
_eclipse_ is this word. Evidently Jesus could not keep Satan from
attacking Peter. He had already captured Judas. Did he not
repeatedly attack Jesus? But he could and did pray for Peter's
faith and his praying won in the end, though Peter stumbled and
fell. {And do thou} (kai su). The words single out Peter
sharply. {Once thou hast turned again} (pote epistrepsas).
First aorist active participle of epistreph(935c), common verb to
turn to, to return. But the use of this word implied that Peter
would fall though he would come back and "strengthen thy
brethren."