All of you have dealt with people who try to justify themselves with a statement that begins, "But God wouldn't want…" What exactly? Me to be unhappy, me to live alone, me to deny who I really am, et cetera ad nauseam. All of the things they are trying to excuse are plainly condemned in the scriptures. Usually we fall into their trap and wind up saying, "Yes, God does want you to be unhappy," and even though we have a qualifying statement after that—like, if it means you can't go to Heaven otherwise—no one will listen because of our culture's blind acceptance of anything that rouses warm, fuzzy emotions. So let's just examine those first four words and leave the rest out.
"But God wouldn't want…" When someone says that, the red flags should start waving in your mind. What exactly are they doing? Presuming to speak for God, that's what. Presuming to know exactly how God does and does not feel, what He does and does not want. False prophets did this when they said they were speaking for God.
And the LORD said to me: “The prophets are prophesying lies in my name. I did not send them, nor did I command them or speak to them. They are prophesying to you a lying vision, worthless divination, and the deceit of their own minds. Therefore thus says the LORD concerning the prophets who prophesy in my name although I did not send them, and who say, ‘Sword and famine shall not come upon this land’: By sword and famine those prophets shall be consumed. (Jer 14:14-15)
Presuming what God would say or do about something and then telling others in his name is presumption. Presumptuous people did not fare well under the Law.
The man who acts presumptuously by not obeying the priest who stands to minister there before the LORD your God, or the judge, that man shall die. So you shall purge the evil from Israel. (Deut 17:12)
But the prophet, that shall speak a word presumptuously in my name, which I have not commanded him to speak…that same prophet shall die. (Deut 18:20)
God does not take it kindly when we take His role, uttering pronouncements as if we were God Himself. In fact, there is a word for that sort of behavior—blasphemy. Think of that the next time you want to do something that He has plainly said he does not approve of, yet you utter those presumptuous words: "God wouldn't want…"
…the Lord knows how to rescue the godly from trials and to keep the unrighteous under punishment until the day of judgment, especially those who follow the polluting desires of the flesh and despise authority. Bold, arrogant people! They do not tremble when they blaspheme the glorious ones. (2Pet 2:9-10)