The boldness (tēn parrēsian). Telling it all (pan, rēsia). See also Act 4:29, Act 4:31. Actually Peter had turned the table on the Sanhedrin and had arraigned them before the bar of God.
Had perceived (katalabomenoi). Second aorist middle participle of katalambanō, common verb to grasp strongly (kata), literally or with the mind (especially middle voice), to comprehend. The rulers recalled Peter and John from having seen them often with Jesus, probably during the temple teaching, etc.
They were unlearned (agrammatoi eisin). Present indicative retained in indirect discourse. Unlettered men without technical training in the professional rabbinical schools of Hillel or Shammai. Jesus himself was so regarded (Joh 7:15, “not having learned letters”).
And ignorant (kai idiōtai). Old word, only here in the N.T. and 1Co 14:24; 2Co 11:6. It does not mean “ignorant,” but a layman, a man not in office (a private person), a common soldier and not an officer, a man not skilled in the schools, very much like agrammatos. It is from idios (one’s own) and our “idiosyncracy” is one with an excess of such a trait, while “idiot” (this very word) is one who has nothing but his idiosyncracy. Peter and John were men of ability and of courage, but they did not belong to the set of the rabbis.
They marvelled (ethaumazon). Imperfect (inchoative) active, began to wonder and kept it up.
Took knowledge of them (epeginōskon autous). Imperfect (inchoative) active again, they began to recognize them as men that they had seen with Jesus.