“When day came,

He called his disciples.

He chose

Twelve of them,

Whom he named apostles.”

καὶ ὅτε ἐγένετο ἡμέρα, προσεφώνησεν τοὺς μαθητὰς αὐτοῦ, καὶ ἐκλεξάμενος ἀπ’ αὐτῶν δώδεκα, οὓς καὶ ἀποστόλους ὠνόμασεν,

Luke said that when daylight or the day came (καὶ ὅτε ἐγένετο ἡμέρα), Jesus called his disciples (προσεφώνησεν τοὺς μαθητὰς αὐτοῦ).  However, he chose twelve of them (καὶ ἐκλεξάμενος ἀπ’ αὐτῶν δώδεκα), whom he named apostles (οὓς καὶ ἀποστόλους ὠνόμασεν).  The number 12 corresponded to the number of sons of Jacob or the 12 tribes of Israel.  These 12 had what was later referred to as apostolic authority.  Jesus thus established or picked out these 12 disciples to carry on his work.  The distinction was that disciples were learners or followers.  The apostles, on the other hand, were to be sent out on a mission to do something.  There is something similar in Mark, chapter 3:13-14, where Jesus called these special disciples, apostles, also.  Jesus called these 12 that he wanted to be with him.  They, of course, came to him.  Matthew, chapter 10:1, said that Jesus gave these 12 apostles authority to cast out unclean spirits just as he had done.  Jesus summoned or called his 12 apostles to give them spiritual authority over unclean or impure spirits.  Thus, they could cast out or banish these evil spirits or demons.  They were also able to cure, treat, or heal all diseases and illnesses, sicknesses, or weakness.  In other words, Jesus was giving his own power or authority to cast out evil spirits and heal people to these 12 apostles.  This was a big deal.