G1492I–εἴδω–eidō

Then the Apostles and Elders met to consider the matter;

ἰδεῖν idein “to understand”

and Paul desiring that he should accompany him on his journey, took him and circumcised him on account of the Jews in those parts, for they all knew that his father was a Greek.

ᾔδεισαν ēdeisan “they knew”

The people, meanwhile, kept shouting, some one thing and some another; for the assembly was all uproar and confusion, and the greater part had no idea why they had come together.

ᾔδεισαν ēdeisan “did know”

"I did not know, brethren," replied Paul, "that he was the High Priest; for it is written, `Thou shalt not speak evil of a ruler of Thy people.'"

ᾔδειν, ēdein “I had known,”

What follows? Is the Law itself a sinful thing? No, indeed; on the contrary, unless I had been taught by the Law, I should have known nothing of sin as sin. For instance, I should not have known what covetousness is, if the Law had not repeatedly said,

ᾔδειν, ēdein “I had known,”

And there shall be no need for them to teach each one his fellow citizen and each one his brother, saying, Know the Lord. For all will know Me from the least of them to the greatest;

εἰδήσουσίν eidēsousin “will know”