The golden rule is present is the most relgions of the world : "Do unto others as you would have them do unto you", Matthew 7:12; this is an affirmation of the rule in the gospel. This rule is also known as spiritual gift of rectitude or imitate God as is explained in Ephesians 5:1: "Be imitators of God".
To enter in the kingdom of God means to accept the rectitude as a path of life ("I am the way, the truth and the life", John 14:6) because our neighbor matters, the Good is expansive. The kingdom of God as the culture of the excelence is basically rectitude.
We have two choose between the good and the evil, the rectitude and the sin, to live according to the spirit or according to the flesh. This is an explanation about the difference between the spiritual man and the natural man.
What underlies the golden rule is the exercise of empathy, the empathy is a faculty of the spirit with the intuition and the inspiration.
The rectitude is the fundament of ethics. An example of this teaching is the parable of the Good Samaritan, Luke 10:25-37:
"A man was going down from Jerusalem to Jericho, when he was attacked by robbers. They stripped of his clothes, beat him and went away, leaving him half dead. A priest happened to be going down the same road, and when he saw the man, he passed by the other side. So too, a levite, when he came to the place and saw him, passed by the other side. But a samarithan, as he traveled, came where the man was; and when he saw him, he took pity on him. He went to him and bandage him wounds, pouring on oil and wine. Then he put the man on his own donkey, brought him to an inn and took care of him. The next day he took out two denarii and gave them into the innkeeper. "Look after him" he said, "and when I return, I will reimburse you for any extra expense you may have"
Which of these three do you think was a neighbor to the man who fell into the hands of the robbers?"
