(Original post by SaintSoldier)
I'm assuming you're talking about marriage here. This article from www.realsikhism.com
should clear things up:
"Sikhs preach to marry a Sikh because of greater compatibility. Sikhs still consider people from all religions equal.
Everyone has a goal in life. If you have a similar goal as your partner, you will achieve that goal with a companion and with less obstacles. However, if you have a goal which varies from your spouse's goal, then you will experience lots of disagreement, arguments, and eventually a lot of obstacles to reach your goal.
Sikhism preaches that the purpose of our life is to become One with God. One can achieve this goal by following Guru's teachings and the lifestyle shown by Sikh Gurus. If one marries a Sikh, they will have the same lifestyle and great compatibility. Husband and wife can help each other and walk hand in hand on the path shown by Sikh Gurus to achieve the goal together.
Sikhs have a great respect for other religions. Sikhs consider all humans as equal. No one is shunned away from entering the Gurdwara Sahib. Everyone eats Langar sitting at the same level on the ground signifying humbleness and equality. Sikhs are not to discriminate based on religion, class, culture, color, ethnicity, or gender. Meaning no one is denied rights because of their looks or which religion they belong to. However, when it comes to marriage, one has to find a compatible match with similar values and beliefs.
This does not mean a Christian, Hindu, or a Muslim is not good enough for a Sikh. The belief system practiced by some Christian, Hindus, and Muslim is not compatible with Sikhism. Sikhs with great respect disagree with some beliefs and practices followed by some religions.
Sikh Gurus' teachings are logical, practical, and moral. One who believes in them and follows them is known as a Sikh. Since the purpose of human life is to become One with God. We should love God, Meditate on Him, and live a lifestyle shown by Sikh Gurus to keep ourselves focused to meet God. Marrying a Sikh makes us stronger and much more focused to achieve this goal."
Rehatname make it clear that Sikhs should only marry Sikhs because we have a common goal, and both the husband and wife can help each other to achieve that goal.
"Have relations with a Sikh of the Guru" (Rehatnama Bhai Chaupa Singh)
"Killing a daughter or to give a daughter (in marriage) to a non-Sikh, such a person commits great offence. Sikh should give his daughter (in marriage) to a Sikh. Thus Gurmukh meets a Gurmukh. Giving a daughter to a Bhadni (non-Sikh) is like giving nectar to a snake." (Rehatnama Bhai Desa Singh)
"A Sikh gives (in marriage) his daughter to a Sikh and does not accept any money in exchange. He is my Sikh and will reach in the Lord's presence." (Guru Pratap Surya)
"When the daughter comes of age only then relations should be contracted, not for a very young girl. And the relations should be Sikhs of the Guru." (Prem Sumagar)
Remember, this does not mean that the Sikhs are entitled to special treatment or are some sort of master race, because Guru Gobind Singh clearly tells us "Recognise the entire human race as one."
I'll put it this way. If your wife is fasting, and making your children fast, but you as a Sikh think this is wrong, then what are you supposed to do? Let your kids fall into illusion and false practices by doing nothing, or harm your relationship with your wife by putting a stop to it? If you're trying to tell your kids the sakhis of the Gurus, and your wife is telling them that they are false prophets, then who are they supposed to believe? This problems woudn't arise in a Sikh marriage.
Come along to the Ask About Sikhism thread if you want to know more