It's not opposite day.
Actually, if it were opposite day, how would you ever know? So I say "today's not opposite day!" and...there you have it. Truth. A simple statement. No reverse psychology, no subtle casuistry. The reason why I think this might end up being a problem is because, say it was opposite day. Follow me here: If I told you it was opposite day, then it actually wouldn't be opposite day. Because if it were indeed opposite day, as I just mentioned, then as the rule applies, it wouldn't be opposite day. But if it truly wasn't opposite day, then the rule wouldn't apply. God help us. So, I guess the only way to truly play the game of "Opposite Day" is to start somewhere in the middle and just (not) go about your (non) business, never declaring the obvious ("today's opposite day!"), because the more you reason it out, the more you're bound to confuse and contradict.
Debate all you want. Multiply dimensions ad infinitum. Go ahead and tell me there's an alternate universe somewhere that is doing everything obversely to us. The point is, logically, semantically, it can never truly be opposite day.
Um, actually it can. Paul writes to Timothy: "And the servant of the Lord must not strive; but be gentle unto all men, apt to teach, patient, In meekness instructing those that oppose themselves; if God peradventure will give them repentance to the acknowledging of the truth". (2 Timothy 2:24, emphasis mine)
And who might they be? "Those that oppose themselves". Weird. This statement introduces self-duality into the equation. How in the world—this world—can you oppose yourself? Paul encountered it in his own life. When he says in his letter to the Romans how he struggled with dueling, dual natures within his body. Wanting to please God, aligning his will with the Will of God. Yet every time he wished to live it out in real-time, something deep down struggled against it. His "flesh", as he refers to it in chapter 7, verse 18: "For I know that in me (that is, in my flesh,) dwelleth no good thing: for to will is present with me; but how to perform that which is good I find not." If you find this struggle going on inside you, as I and every other Christian will and has, then take heart! You're not alone.
"I thank God through Jesus Christ our Lord. So then with the mind I myself serve the law of God; but with the flesh the law of sin." (Romans 7:25)
The internal struggle of our-own-will-versus-God's is going on all the time. The choice between selfish, self-service and the willingness to forsake that option in light of what God wants, is presented before us all the time. Each decision, leading the direct opposite direction from the other. God says through Moses in Deuteronomy (30:19, emphasis mine), "I call Heaven and earth to record this day against you, that I have set before you life and death, blessing and cursing: therefore choose life". Simple enough, right? How many of us realize the path down which all our bad decisions lead? "But every man is tempted, when he is drawn away of his own lust and enticed. Then when lust hath conceived, it bringeth forth sin: and sin, when it is finished bringeth forth death." (James 1:14-15) Choose life, says God. Shouldn't that appear on God's commandment list? I suppose anytime we obey Him, we choose life. I like that. And the obverse, the opposite would be...? Figure it out.
Paul writes to the Galatians and says something interesting. He says "I am crucified with Christ, nevertheless I live; yet not I, but Christ liveth in me: and the life which I now live in the flesh (i.e. his physical body) I live by the faith of the Son of God, who loved me, and gave Himself for me." Here, he's saying that God, through Jesus' atoning sacrifice, has given him another life, another nature. And never the twain shall meet. David says "As far as the east is from the west, so far hath he removed our transgressions from us." (Psalm 103:12) You can't get more oppositional than that. And that is exactly what happens when we believe on and in Jesus.
So, with reference to "those that oppose themselves", Paul is talking about Christians who have received God's new nature at the very depth of their being and yet, somehow, are living in opposition to it. Guilty as charged. This is actually really good news. How many Christians walk around knowing and that "old things have passed away; behold, all things are become new" (2 Corinthians 5:17)? Regardless of whether we realize it or not, we have been changed for the better. Notice the second part of the verse in 2 Timothy: "God will give them repentance to the acknowledging of the truth." What truth? The truth that you are not who you used to be after believing in Jesus.
Stop opposing yourself. Choose life.