A killjoy is “ a person who deliberately spoils the enjoyment of others through resentful or overly sober behavior”.37
Resentful means “feeling or expressing bitterness or indignation at having been treated unfairly”38
The other meaning of this Parable has to do with why the father was not being unfair to the older son – what he was trying to explain to explain to the older son is:
God’s statement:
They are even. They are both equally loved.
Bias means “prejudice in favor of or against one thing, person, or group compared with another, usually in a way considered to be unfair”
Question: Please confirm.
God’s answer:
‘My son, you are here with me always; everything I have is yours. But now we must celebrate and rejoice, because your brother was dead and has come to life again; he was lost and has been found.’” (This was Father’s response to the older son)
38 'Resentful: Definition Of Resentful In Oxford Dictionary (American English) (US)' (Oxforddictionaries.com, 2016) <http://www.oxforddictionaries.com/us/definition/american_english/resentful> accessed 24 May 2016.