Being assembled together with them (sunalizomenos). Present passive participle from sunalizō, an old verb in Herodotus, Xenophon, etc., from sun, with, and halizō, from halēs, crowded. The margin of both the Authorized and the Revised Versions has “eating with them” as if from sun and hals (salt). Salt was the mark of hospitality. There is the verb halisthēte en autōi used by Ignatius Ad Magnes. X, “Be ye salted in him.” But it is more than doubtful if that is the idea here though the Vulgate does have convescens illis “eating with them,” as if that was the common habit of Jesus during the forty days (Wendt, Feine, etc.). Jesus did on occasion eat with the disciples (Luk 24:41-43; Mar 16:14).
To wait for the promise of the Father (perimenein tēn epaggelian tou patros). Note present active infinitive, to keep on waiting for (around, peri). In the Great Commission on the mountain in Galilee this item was not given (Mat 28:16-20). It is the subjective genitive, the promise given by the Father (note this Johannine use of the word), that is the Holy Spirit (“the promise of the Holy Spirit,” objective genitive).
Which ye heard from me (hēn ēkousate mou). Change from indirect discourse (command), infinitives chōrizesthai and perimenein after parēggeilen to direct discourse without any ephē (said he) as the English (Italics). Luke often does this (oratior ariata). Note also the ablative case of mou (from me). Luke continues in Act 1:5with the direct discourse giving the words of Jesus.