Using Scripture in a "secular" argument
For a long time, I operated under the assumption that Christians should not use Scripture in debates over public policy. Pagans will reject Scripture outright, so we must instead use "reason" to convince people of the validity of our arguments regarding controversial moral issues of our day.
This is because I am so much wiser and more intelligent than God, and so much more convincing.
This strategery fails on several points. First, those who reject Biblical moral law are going to reject it whether it's based on "reason" or Scripture. The basic problem we face on matters of morality is that we live in an increasingly post-Christian society, and the battle we face is spiritual, not political or cultural. (See Ephesians 6:12.) We are fools if we think the arguments of a feeble human mind are going to be more powerful than the Word of God itself.
Second, using Scripture in public debates is evangelistic. The Bible is "quick, and powerful, and sharper than any twoedged sword." (See Hebrews 4:12.) When we use the Word of God, not only are we using the most powerful weapon available, we are convicting the hearts of sinful men. We are commanded to "teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost: Teaching them to observe all things whatsoever I have commanded you." (See Matthew 28:16-20.) There is no better way to do that than with Scripture.
Third, when we carefully avoid using Scripture in favor of our own "reason" and logical argumentation we are actually worshiping ourselves. Do we actually believe that the arguments we craft on issues like abortion and sexual morality will be superior to what our Father has written for us? Do we really have such a high view of ourselves that we need to run interference for God? What unbridled arrogance!
When we go into spiritual battle without God's Word, we are leaving our sword behind and using our bare hands. That is foolish. There is and cannot be any better weapon than Scripture.