13.  And He went up on the mountain and called to Him those He Himself wanted.  And they came to Him.

Now the Lord leaves the crowd to go up on the mountain.  It does not say which mountain, but the expression would indicate that this was a well-known retreat that the Lord often resorted to.  While there, He calls to Him those He wants to come, and they leave all behind to come to Him.  These were devoted people, and they will be rewarded by our Lord for their devotion by being those He calls to service.

14.  Then He appointed twelve, that they might be with Him and that He might send them out to preach,

The Lord has two great tasks for those He calls to be His twelve: both that they will be with Him and that they will be sent out to preach.  The word for sent here is the Greek word apostello.  The noun form of this word is “apostle,” and so what this means is that He was apostling them to preach.  An apostle is one who is sent with authority or commissioned.  Thus, these men were not just sent, but sent with authority from our Lord Himself to preach the message they were given.  What they are sent to preach is not mentioned here as it was in Matthew, where we learn that it was that the Kingdom of God was at hand.

Notice that these men cannot perform these tasks at the same time.  When they are with the Lord, they are not sent out preaching, and when they are sent out preaching, they are not with the Lord.  In the same way, we need to consider that we as servants of our Lord likewise have two tasks.  We must both spend time with our Lord and get to know Him better, and go out and tell others about Him.  We cannot just focus on spreading the Word or we will neglect getting to know the Lord ourselves.  And we cannot just study and learn, for then we will be neglecting telling others and spreading the good news.  We would do well to consider these two tasks that the twelve had, and realize that we need to concentrate on both ourselves.

15.  And to have power to heal sicknesses and to cast out demons:

This is more of what they are sent out to do.  They are not just given the authority to preach, but also to work miracles to prove the truth of their words.  They are given power both over sicknesses and over the demons, the followers of the enemy.

16.  Simon, to whom He gave the name Peter;

Simon is listed as the first of the disciples called.  Indeed, He was one of the three to whom the Lord gave the greatest of His revelations while He was on earth.  To him the Lord gives a name.  This does not replace his name of Simon, but rather is added to it, much like a last name or a middle name today.  “Peter” means “stone,” and so we might say that the Lord called him Simon Stone.

17.  James the son of Zebedee and John the brother of James, to whom He gave the name Boanerges, that is, “Sons of Thunder”;

These two, along with Simon, form the three whom the Lord granted the highest position among the twelve.  These two also are given a surname, Boanerges, which means “Sons of Thunder.”  Thus, they are James and John, Sons of Thunder.  Boanerges is an Aramaic word.  In Hebrew, which is akin to Aramaic, “Thunder” is the word kol, which means “voice,” the idea being that it is the voice of God.  This may be the idea that the Lord is referring to here.  These men were indeed destined to speak for God.

18.  Andrew, Philip, Bartholomew, Matthew, Thomas, James the son of Alphaeus, Thaddaeus, Simon the Canaanite;

These eight are also called as part of the twelve.  Here, Andrew is listed separately from his brother Simon so that Peter could be connected with James and John as the three special disciples.  The same is true in John, whereas in Matthew and Luke Andrew is mentioned with his brother and thus divides him from James and John.  “Andrew” is a Greek name meaning “manly.”

Philip and Bartholomew are listed next.  Bartholomew is apparently one of two names this disciple had, the other being “Nathanael.”  In John, Philip and Nathanael are connected as friends, whereas in the lists of the twelve Philip and Bartholomew are always listed together.  Moreover, in John 21:2, Nathanael is listed with others of the twelve.  These facts lead to the conclusion that Nathanael and Bartholomew are probably the same person.

Matthew, of course, is the disciple who wrote the first of the gospels presenting the Lord as King.  He was also named Levi, and had been a tax collector until the Lord called him.

Thomas is an Aramaic name.  In Greek his name is “Didymos,” and he is called that in John 11:16.

James the son of Alphaeus and Thaddaeus are next mentioned.  Thaddaeus was his last name, his first name being Lebbaeus.  In John 14:22 he is called Judas not Iscariot, for Judas and Thaddaeus mean the same thing: “beloved child.”

Simon the Canaanite was not a Gentile, as the name would seem to imply.  The idea is a Canaanaean, otherwise known as a Zealot.  This group believed strongly in the idea that Yahweh had given the land of Israel to His people, and that the Roman presence there was a direct affront to God.  They were constantly involved in attempts, violent or otherwise, to get the Gentiles out of the land.  Now, however, this Zealot becomes part of a different group, and gives his allegiance to a higher cause than the restoration of the land to the Israelites.  Now he swears allegiance to the Lord of the Land Himself, and puts aside his zealous past to follow the humble Servant Whom God sent.  Note that he did not necessarily put aside all of his zealous beliefs just because he followed Christ.  The Lord never opposed the Romans during His ministry, but neither did He endorse their presence there.  Simon was no doubt not the only disciple who hoped that Christ might rise up in power and cast the Romans from the land. 

19.  And Judas Iscariot, who also betrayed Him.  And they went into a house.

The last disciple listed is Judas Iscariot, the one who fell from his position when he delivered the Lord to His enemies.  He is also named Judas (like Thaddaeus,) but this beloved child rejected the love offered to him and chose instead rebellion and betrayal.

Now, having chosen His twelve, they enter together into a house.  Whether this house is on the mountain mentioned in verse 13 or whether they came down from that mountain to enter it is hard to say.  Often events that are far apart in time are tied closely together in the brief record of events given in the gospels.
20.  Then the multitude came together again, so that they could not so much as eat bread.

The multitude crowds into the house after them, so much so that they do not even have room to eat.  This could mean that the house mentioned was the Lord’s Own house in Capernaum, and that the people there were waiting for His return, knowing that He must eventually come there.