G4417–πταίω–ptaiō

I say, then, Did they stumble that they might fall? let it not be! but by their fall the salvation `is' to the nations, to arouse them to jealousy;

ἔπταισαν eptaisan “they did stumble”

for whoever the whole law shall keep, and shall stumble in one `point', he hath become guilty of all;

πταίσῃ ptaisē “may stumble”

for we all make many stumbles; if any one in word doth not stumble, this one `is' a perfect man, able to bridle also the whole body;

πταίομεν ptaiomen “we stumble”πταίει, ptaiei “does stumble,”

wherefore, the rather, brethren, be diligent to make stedfast your calling and choice, for these things doing, ye may never stumble,

πταίσητέ ptaisēte “shall you stumble”