Hello again @throughfaith, in Matthew 10, the Lord Jesus "summoned/called" (proskaleomai) His Apostles to Himself, gave them power, and then sent them forth to minister to the people (to preach, to heal the sick and the blind, to cast out demons, etc.). The Twelve Apostles (at this point in time .. Matthew 10) had already been "chosen" (eklegomai).
Luke 6
12 It came to pass in those days, that He went out into a mountain to pray, and continued all night in prayer to God.
13 And when it was day, He called unto Him His disciples: and of them He chose/(eklegomai) Twelve, whom also He named Apostles.
Matthew 10
1 When He had called/summoned (proskaleomai) unto Him His Twelve disciples, He gave them power against unclean spirits, to cast them out, and to heal all manner of sickness and all manner of disease.
His disciples, which now included His chosen Twelve, were there with the multitudes to hear His sermon that day (the sermon that we refer to as, "The Beatitudes").
~Deut
Luke 6
12 And it came to pass in those days, that He went out into a mountain to pray, and continued all night in prayer to God.
13 And when it was day, He called unto Him His disciples: and of them He chose twelve, whom also He named Apostles;
14 Simon, (whom he also named Peter,) and Andrew his brother, James and John, Philip and Bartholomew,
15 Matthew and Thomas, James the son of Alphaeus, and Simon called Zelotes,
16 And Judas the brother of James, and Judas Iscariot, which also was the traitor.
17 And He came down with them, and stood in the plain, and the company of His disciples, and a great multitude of people out of all Judaea and Jerusalem, and from the sea coast of Tyre and Sidon, which came to hear Him, and to be healed of their diseases;
18 And they that were vexed with unclean spirits: and they were healed.
19 And the whole multitude sought to touch Him: for there went virtue out of Him, and healed them all.
20 And He lifted up His eyes on His disciples, and said,
Blessed be ye poor: for yours is the kingdom of God................................................