(Red-letter portions of the new Testament)
Matthew 5:45, "...be sons of your Father in heaven. He causes His sun to rise on the righteous and the unrighteous."
Jesus says that the way we show that we are children of the Heavenly Father is to let our sunny and refreshing personality be a blessing to everyone, not just to people we like or who like us. God blesses all people with sunshine and rain.
Contrary to religious myth, God doesn't just prosper the righteous. God's creation is so bountiful that even those who couldn't care less about God still reap the benefits of His generosity to mankind.
We show ourselves to have our Father's traits when we are so generous in spirit that even our enemies are blessed. A leopard cannot change its spots. Neither can a child of God be generous to one person, while withholding from another.
When we give our life to Jesus, love Him so devotedly, and allow His Spirit to fill us, we are born again with a new heredity. We go through a spiritual gene-replacement surgery. We are forever different, not just in outward activity, but new in character, personality, and spirit
If you are a child of Father, don't allow your traits to be covered up by worldly attitudes. When you are tempted to snub a person, because he is your adversary, don't. Don't mask your heredity with the fashion and cosmetic attitudes of the world. When you dress in the bigotries of the world, that discriminate and separate by who is acceptable and who isn't, you begin to act like a child of the world, instead of the Heavenly Father.
"Don't conform any longer to the pattern of this world, but be transformed by the renewing of your mind, so that you may prove what God's will is...His good, pleasing and perfect will." Romans 12:2
You are not the world's child, are you? Let your new heredity shine from the inside out. Be generous in spirit, like your Father.