The Twelve Apostles were Peter, Andrew, James the Greater, James the Lesser, John, Philip, Bartholomew, Matthew, Thomas, Thaddeus (Jude), Simon and Judas Iscariot.
Peter and his brother Andrew were fishermen, Simon and Judas were zealots and Matthew was a tax collector. Most Jews hated the tax collectors as they robbed their own peoples meager earnings to stuff the rich coffers of the Roman empire, they were considered to be traitors to their own people and yet Jesus chose one as His disciple, His messenger to the world.
And the zealots like Simon and Judas wanted a military victory over Rome. Yet Jesus taught that we should love our enemies and turn the other cheek and so these teachings must've taken much humility to absorb.
None of the Apostles were scholars, none were Sanhedrin, Sadducees or Pharisees. As such they were nothing special, no one worth listening to according the the religious elite.
And yet what these 12 men had to say changed the world.
Because after Jesus' time on Earth had passed, they were the only 12 disciples Jesus had left, they are the ones who grew the church and preserved the Gospel in ink.
These were ordinary men, just like most of us but why would they be chosen if they were not special in some way?
We are all chosen but I think being humble and honest with yourself and God about your short comings is what they had that many do not. The thing about people who are extraordinary is that their egos are also extraordinary whereas the Apostles were humble before The Lord.
One parable I think may have actually been about Matthew appears in a brief passage of scripture:
10 Two men went up into the temple to pray; the one a Pharisee, and the other a publican.
11 The Pharisee stood and prayed thus with himself, God, I thank thee, that I am not as other men are, extortioners, unjust, adulterers, or even as this publican.
12 I fast twice in the week, I give tithes of all that I possess.
13 And the publican, standing afar off, would not lift up so much as his eyes unto heaven, but smote upon his breast, saying, God be merciful to me a sinner.
14 I tell you, this man went down to his house justified rather than the other: for every one that exalteth himself shall be abased; and he that humbleth himself shall be exalted. Luke 18:10-14
The Pharisee brags to God about how he is so much better than those people like sinners, theives and tax collectors. Whereas the tax collector humbles himself, beats his chest and begs for forgiveness and Jesus says he is justified before God not the Pharisee.
This humble attitude of the tax collector I would think is what each of the 12 had that made them stand out and be receptive to Jesus' message.
Each of us is called to be a disciple just as the 12 were. And each of us have sinned, just as the 12 had. But if we repent and humble ourselves we too my be chosen and not simply called.
The 12 seem to have gotten along rather well. And trial by fire usually invites a strong bond to form but they all came from such radically different backgrounds it could not have been easy. You had those that may have been more pacifist in nature clashing with the zealots of the group while others like Mary Magdelene who may have had more money clashing with the simple fishermen who never knew what having enough was like much less plenty.
For the sake of Christ they pulled together and did what they had to do to preach the message.
But they didn't quite make it at first. They had some technical difficulties.
15 Lord, have mercy on my son: for he is lunatick, and sore vexed: for ofttimes he falleth into the fire, and oft into the water.
16 And I brought him to thy disciples, and they could not cure him.
17 Then Jesus answered and said, O faithless and perverse generation, how long shall I be with you? how long shall I suffer you? bring him hither to me.
18 And Jesus rebuked the devil; and he departed out of him: and the child was cured from that very hour.
19 Then came the disciples to Jesus apart, and said, Why could not we cast him out?
20 And Jesus said unto them, Because of your unbelief: for verily I say unto you, If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you. Matthew 17:15-20
Peter was one who could walk on water by faith one moment and find himself sinking in doubt the next. But He grew into the leader Jesus needed and had envisioned.
Saul of Tarsus was a zealot who was responsible for the murder of the first Christian martyr Stephen. But hot on the trail of the Jesus movement on the road to Damascus he was blinded by the light of Christ and Jesus asked him why he was persecuting Him. Jesus seemed to feel that attacks against His flock were attacks against Him, as I'm sure He feels when any of us fights another either physically or verbally.
But when Saul was converted he changed his name to Paul. And he then wrote 2/3 of the New Testament. So just because someone has an ugly past does not mean they can't create a beautiful future.
So no matter how unworthy you may feel, no matter how ugly your past, the Atonement is available to all as many times as you need it to get back on track. No matter how ordinary you may feel, no matter how unskilled you may be all you need to answer the call of discipleship is to be humble, repentant and cultivate a strong faith but even faith as insignificant as a grain of mustard seed can move mountains.