Just to add few more qoutes from gurbani regarding caste
No one should be proud of his caste.
He alone is a Brahmin, who knows God. || 1 ||
Do not be proud of your caste, you ignorant fool!
So much sin and corruption comes from this pride.||1|| Pause||
Everyone says that there are four castes, four social classes.
They all emanate from the God’s Seed. || 2 ||
The entire universe is made of the same clay.
The Potter has shaped it into all sorts of vessels. || 3 ||
The five elements join together, to make up the form of the human body.
Who can say which is less (inferior or bad), and which is more (superior or good)? || 4 ||Says Nanak, this soul is bound by its actions. Without meeting the True Guru, it is not liberated (SGGS 1128).
There is no place for caste system in Gurmat. Sri Guru Nanak Dev Ji introduced the concept of a society with no caste distinction. This concept was followed through by all Gurus.
What is ignorance or darkness? Material or body consciousness, which gives rise to false ego, is ignorance. Contrary to this, spiritual consciousness is light. Therefore, according to Gurbani, spiritual blindness is the root cause of this disease called pride of caste.
Recognize the Lord’s Light within all, and do not inquire or consider caste, as there is no caste in the world hereafter (SGGS 349).
What merits is in the caste? Truthfulness is measured within. Pride in one’s caste is like poison—he who taste it will die (SGGS 142).
Man's body and caste will not go with him to the world hereafter. Where one is called to answer for his account, there, he will be emancipated only by the practice of Truth (SGGS 112).
Ego, self-centeredness, excessive anger and pride are the caste of men (SGGS 429).
This is the nature of ego, that people perform their actions in pride (SGGS 466).
The Lord is in the soul, and the soul is in the Lord. This is realized through the Guru’s Teachings (1153).
The caste of God is castelessness; He is unborn, self-illumined, without desire and doubt (SGGS 597).
Gurmukh jaat pat sach soi: God is the caste and honor of the Gurmukh (SGGS 560).
The Unique Lord is Peerless, Immortal, unborn, and without caste and involvement (SGGS 838).
(Before material creation) neither there was female, nor male, nor caste, nor birth nor did any one suffer pain or pleasure (SGGS 1035).
God has no color, caste and mark; by His Will, He creates the whole world (SGGS 1075).
The above verses of Gurbani make it very clear that the Lord is casteless. The Lord has no ancestry or family. Therefore, the Self or the soul made in His image is also casteless.
“What makes you a Brahmin and I merely a Shudra ? If bloodruns in my veins, does milk flow in yours? "- Guru Granth Sahib Ji, Rag Gauri, Page 324
Gurmukh
A Gurmukh is a Self-Realized person. Through the grace, he has killed his inner ego. He is jealous of no one; he has become the dust of all; and he ever recites the Nectar Name in the society of the true devotees. Through his selfless devotion, he is completely immersed in the Infinite Consciousness, Waheguru.
A Gurmukh is casteless. As the Infinite Consciousness or Waheguru is casteless, so is His true devotee. His all actions are selfless. He is purified in and out. He Sees the All-pure in all. He is spiritually wise, and knows the essence of the Divinity. This is the sign of a true Sikh or a spiritual disciple.
According to Gurbani, a Gurmukh or a true Sikh only identifies with Shabad or Naam, the Lord's name. He sees Waheguru as all there is; in everything, everywhere, and beyond measures. That 's his casteless caste!
God's Name is the caste, honor, and glory of the True Sikh or Gurmukh (SGGS 230).
The caste and honor of the Lord's devotees is His Naam (SGGS 768).
The Name is my caste and honor (SGGS 353).
God is the caste of the saintly person. You are the Lord; I am just Your puppet (SGGS 667).
The Name is my caste, the Name is my honor, and the Name is my family (SGGS 713).
Thus, a pure Sikh or a devotee is beyond any mundane caste and false pride. Because of his pure love and devotion for God, he depends only on God. For that, God is his caste, honor, glory, family, etc.
According to Gurbani a Gurmukh, a true Sikh or a devotee, is the best among all. He has the intellect and capacity to comprehend the source of the universe. He is knower of the God, and constantly stays linked to Him. His perception is through intuition. Such Gurmukh or a true Sikh is the Self-Realized or God-intoxicated person. He is fully immersed in the pure love and devotion of the Lord. Except for the Waheguru, he knows that everything else is of impermanent nature.
Effacing my caste, I have become the Lord's courtier (SGGS 875).
Spiritually elevated person is wisdom-guided. He sees God within an without. Such individual expresses God through his God-guided intelligence, discrimintive thoughts, and God-centered spiritual activities.
He dwells in a broken-down shack, in tattered clothes, with no social status, no honor and no respect; he wanders in the wilderness, with no friend or lover, without wealth, beauty, relatives or relations. Even so, he is the king of the whole world, if his mind is imbued with the Lord’s Name. With the dust of his feet, men are redeemed, because God is very pleased with him (SGGS 707).
by Tara Singh
"Sikhs are gradually weakening themselves by creating social distinctions within Sikhism" (Patwant Singh The Sikhs, page 255)