Luke 15  The Pharisees and scribes derided Jesus because He received sinners.  He accepted and welcomed them... He admitted them into His Presence - showing hospitality.   Jesus gives 3 illustrations that show God's heart and will in this matter.

Verses 4-7  The lost sheep - these men could relate to the importance of finding even 1 missing sheep from their flock.  They would rejoice when it was found.  Yet they couldn't find any joy in one lost man coming to God.  " I tell you that in the same way there will be more joy in heaven over one sinner who repents, than over ninety-nine righteous persons who need no repentance."  

Verses 8-10 The lost coin - A woman who has lost one coin is desperate to find it again. It is vital to her well-being. She rejoices when she finds it.  Again Jesus tells them that all of heaven will rejoice over a sinner who repents.

Verses 11-32 - The lost son - The rebellious son who takes his inheritance, leaves his father and wastes all that he has... who then becomes destitute and returns home; humbled and repentant.  This son is received with honor and great joy!  He had been lost - but now is found!  What joy this brought to the father's heart.   Yet, we also see that the elder son has no joy in his brother's return.
The Pharisees and scribes had no joy in seeing sinners repent and be received by Jesus.  Their hearts were so darkened that they couldn't see this fundamental Truth - that God desires all men to repent and come back to Him.

A footnote in my Bible says this, " In these three parables, one basic element is fundamental; the father who loses his son, the woman who loses her coin, and the shepherd who loses his sheep, do not give up the right of ownership.  In the same manner, God is presented as still claiming His right of ownership even of those who are lost. When they are reclaimed, it is not He who becomes their Father or their rightful owner, but they become His again...."

The returning son illustrates what repentance really means -
He reconsiders his decisions and changes his mind about his life choices.
He turns back towards home and to his father.
He recognizes his father's ability to provide but also his unworthiness to receive.
He comes with humility, confessing his sinfulness and unworthiness.
And the father receives him fully! With joy and compassion. With perfect forgiveness and love.

Even more so, does our Heavenly Father receive us when we return to Him.

Which takes us back to that word - receive - ( prosdechomai) - to admit, to await, accept, allow, look for, take... to be hospitable towards.  Romans 12:13 "... practicing hospitality"  is something that we are to do as followers of Christ; as living sacrifices, with transformed lives and renewed minds. The Greek word for hospitality is philonexia - to entertain strangers; to be fond of guests.  We recognize that philadelphia means brotherly love; and that philanthropy is a fondness for mankind.  Hospitality pushes us a little further outside our comfort zone.  To receive others... the lost, the strangers, the rebellious, the sinners - means that we admit them into our homes and into our hearts.  We accept them and show kindness and love - fondness for them.  

The older son could not do that even for his brother.
The Pharisees and scribes could not do that even for their fellow countrymen.
But, Jesus did it all the time.  It is the Father's will.  In Matthew 18:12-14 the parable of the lost sheep is presented again.  But, Matthew adds these words in verse 14, " Thus, it is not the will of your Father who is in heaven that one of these little ones perish."  
"For the Son of Man has come to save that which was lost." ( Matthew 18:11)
We are to receive the those who humble themselves and come to Jesus just like a little child. We are to show love and fondness and kindness to brothers and to strangers.
This brings joy in heaven and will also bring joy to earth for those who love Jesus!

Heavenly Father, lead us in Your wonderful and kind ways.  Forgive us for not loving and receiving strangers and friends as we should. Fill our hearts with Your love and grace and may we see others, especially the lost, through Your eyes and with Your love for them.
In Jesus we ask this,
Amen