George F Somsel wrote:It appears that ἀπό signifies "away from" whereas ἐκ indicates movement "out of" something.
They are pairs which switch between broader story-telling (intended perception of aspect) context and narrow context. As a consequence of the scope of the context, we render things as either "out of" or "away from" in English, as George says, but that is for expediency
in Enlgish, not the meaning
In Acts 22:18, καὶ ἰδεῖν αὐτὸν λέγοντά μοι, Σπεῦσον καὶ ἔξελθε ἐν τάχει ἐξ [no thought given to where he might go when he has left the city gate] Ἱερουσαλήμ· διότι οὐ παραδέξονταί σου τὴν μαρτυρίαν περὶ ἐμοῦ. In this small picture context, the discussion takes place concerning problems that he will face in the city he is asked to leave. There is no need to put Jerusalem in a wider context. For English speakers, you could say "get out of" Jerusalem, or something similar.
In short, you need to look at the larger story or message of these instances to see the significance of choosing ἀπό (broad context) or ἐκ (small context), and so too the other pairs with verbs of motion. Where there is editorial discrepency, I understand that one editor seeing that the action should have been better expressed in a big context, while another saw it as in a specific limited context. Perhaps you could say a minor difference in perception, rather than a major difference in meaning.
Matthew 13:1 Ἐν δὲ τῇ ἡμέρᾳ ἐκείνῃ ἐξελθὼν ὁ Ἰησοῦς ἀπὸ [he had to walk some distance to get to the sea - in the NA/UBS text that is not made clear] τῆς οἰκίας ἐκάθητο παρὰ τὴν θάλασσαν. 2 Καὶ συνήχθησαν πρὸς [they came from a wide area a very broad picture] αὐτὸν ὄχλοι πολλοί, ὥστε αὐτὸν εἰς [in this phrase we consider a very narrow action in focus] τὸ πλοῖον ἐμβάντα καθῆσθαι· In verse 4 ἃ μὲν ἔπεσεν παρὰ τὴν ὁδόν· the road is considered in a wider context of the ground beside it - not just in the narrow context of itself - and we are led to imagine the ἐν τῷ σπείρειν αὐτόν (his hand movement) as covering the road and the ground beside it. Additionally the ἦλθεν τὰ πετεινὰ καὶ takes place in that broader context picture (in which we imagine both road and ground). For expediency in English, we might say "next to" because in larger context picture we see the road and the ground near it / next to it, and express that.
If the difference between expediency in translation and the way Greek expresses thing is difficult to grasp, consider the inceptive imperfect. It doesn't mean
"begin", the present stem implies enthusiasm or the like, and it is the feeling that you have when you begin to do a thing (like learning Greek) that there is some passion, before the hard work, determination / habit without initial excitement kicks in. The imperfect describes the feelings that exist at the beginning of an action, and it is conveniently rendered as "begin to" in English. In doing that we have changed from feelings
of the doer to an understanding in time
. The feeling - the amount of enthusiasm or passion - dictates the number times or length of time, but for convenience we understand it in that way. Of course expediency is not bad, but we are trying to learn the Greek idiom, not just how to be expedient.