G4417–πταίω–ptaiō

So I say, Were their steps made hard in order that they might have a fall? In no way: but by their fall salvation has come to the Gentiles, so that they might be moved to envy.

ἔπταισαν eptaisan “they did stumble”

For anyone who keeps all the law, but makes a slip in one point, is judged to have gone against it all.

πταίσῃ ptaisē “may stumble”

For we all go wrong in a number of things. If a man never makes a slip in his talk, then he is a complete man and able to keep all his body in control.

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

For this reason, my brothers, take all the more care to make your selection and approval certain; for if you do these things you will never have a fall:

πταίσητέ ptaisēte “shall you stumble”