Its always better to let the Bible speak for the Bible. Regardless of political persuasion, when someone posts a comment that errantly cites a Biblical principal or quote, the commentor's credibility is diminished. Christians often misquote and misinterpret the Bible, which makes them appear doubly ignorant. Hopefully this post will start a conversation that, in some way, may help the dialogue that occurs when the present day conversation crosses paths with Scripture.
Errors come in different categories. Some are simple misquotes, which strain credibility, but no malice is apparent. Some are malicious misuse of the Bible, where one cherry-picks the Scriptures out of context in an effort to borrow the Bible's credibility. The latter is known as eisegesis, and it has no place in a fair-minded debate. Again, it is always best to let the Bible speak for the Bible.
A common, benign misquote of the Bible is "God will never put on you more than you can bear". That quote actually does not appear in the Bible.
1 Corinthians 10:13 states "The temptations in your life are no different from what others experience. And God is faithful. He will not allow the temptation to be more than you can stand. When you are tempted, he will show you a way out so that you can endure."
Aside from the misquote, there are a variety of theological reasons that the former is a well-intended error, and it mildly reduces the user's credibility.
Here is the part where commentors foul all credibility: malicious misuse of Scripture. "Jesus never said one word about homosexuality or abortion". This is not a true statement, and is usually used by people who are trying to discredit Christians. Users of this ruse commit eisegesis, in that they impose upon Jesus a unique way of saying what they want to say, and then blame Jesus for not saying what they want. What Jesus did say is very powerful, and it proves He directly addressed traditional marriage, and murder; the defacto points of contention here.
Start with homosexuality and SSM. In Matthew 19:5, Jesus specifically and affirmatively states that marriage is between one man and one woman. Any other union is, by default, unrecognized by God. The Apostle Paul, writer of 13 books of the Bible, expressly denounces homosexuality in Romans 1:26-31. To say Jesus never said homosexuality is wrong is a false premise. His will is made abundantly clear in His own words, and supported with additional New Testament text. This harmonizes with Leviticus 20:13. Bible scholars would call this sound exegesis. Good news for those who may commit this sin - it is a sin like all other sin, and the New Covenant calls for forgiveness of the believer, not the Levitical stoning.
Let's move on to abortion. "Jesus never mentioned abortion". This is a red herring, as abortion was not even an issue to be addressed 2000-3500 years ago. Jesus does specifically address murder in Matthew 19:18. Abortion was not a wide-spread issue in the mainstream of society until Britain outlawed it in 1803. Killing of the innocent is consistently enjoined throughout the Bible, and sound exegesis cannot find another conclusion. The hair-splitting topic of right and wrong relating to abortion can be addressed in another forum, but Biblically it is the killing of an innocent human being and as such is murder, and Jesus did speak to it.
It is encouraging that people care what the Bible says about any particular issue. When treated correctly, the Bible has never been proven wrong. I should mention that the Bible has often been misused, even by Biblical scholars. It was never designed to be a science text, and those who try to discredit it as such are mistaken, and likely misleading.
The majority of the Bible is fairly plain-spoken, although there is a tremendous depth to learning to interpret it. Ockham's Razor often applies, and if one gets into prophecy or period-specific language, a competent, seminary-trained scholar can usually guide you to the correct answer. But, get your final answer from what the whole Bible says, not just from a piece or two, or a person or two.
One last word - let the Bible speak for the Bible. People make a poor filter for Scripture.