Luck is the concept of an improbable event happening through random chance- the outcome is beyond the control of the person affected. If the improbable event has a positive outcome, it is considered good luck, if it has a negative outcome, it is considered bad luck.  

Wishing someone good luck then is to wish that they find a positive outcome in something beyond their control.  

Is luck an anti-biblical concept? 
I have had several Christians through my life gently rebuke me for saying something like “good luck!”, because, they will say, there is no such thing as ‘luck’; God is in control of everything.  

I would still allow for something like improbable events happening through random chance. Even granting predestination, all one has to do is accept a version of middle knowledge in order to include that in any possible combination of outcomes, improbable events happen by chance.  

If a reader is unsure of what is meant by middle knowledge, let me explain it very briefly. 

Middle knowledge is a possible explanation of how human free-will can coexist with divine sovereignty. 

The basic problem is that if God is absolutely sovereign and has chosen the outcome of the world, then humans have no real choice in the matter. They will do what they were predestined to do so that the outcome will arrive at what God wants. 

To keep things simple for this thought experiment, we’ll suppose three possible outcomes if God were to leave humans to their own choices: A, B, and C.  

Middle knowledge is the proposal that God has several layers of knowledge: the highest level is the knowledge of all three outcomes, each of which we might call a possible world, meaning just that in each, this would be the world that would happen if human decisions went one way. So at the highest level, God knows how each of the three worlds would play out.  

The lowest level of knowledge would be knowing how the specific world we are living in right now will play out. 

The middle knowledge is His choice of which one He wants to come to pass. 

Middle knowledge is the proposition that God will choose one of the three possible worlds, and that is His sovereign will; but also recognizing that in any of those three possible worlds, the conclusion is derived from humans freely making choices. 

I limited the possible choices to 3, but consider the actual possible worlds nearly limitless. In this way, one can reconcile human free will with divine sovereignty. 

Some would argue that humans don’t have free will. The biblical story of Saul’s choices would confirm that humans are indeed freely making choices, since Samuel pointedly tells Saul that had he chosen differently, his kingdom would have endured. If there were no other possibility, then Samuel could not have made that statement. So humans are choosing freely, even within a paradigm of divine sovereignty.  

The fact that God chose one of those scenarios of course means that the outcome is determined in the particular scenario chosen by God, but still, no matter which scenario God chose, there are plenty of acts of human will and decision, and within the realized world, there will be improbable events that happened through the random chance of those decisions. 

So the concept of luck isn’t ruled out by Divine sovereignty. I also acknowledge that there are things that will happen that may seem like luck, yet were purposed by God. It’s impossible for any of us to know which events are random and which are specifically designed, but I see no reason why there would not be instances of luck in any world. 

My conclusion is then that luck, per se, isn’t an anti-biblical concept. 

I hope I adequately explained myself about the reconciliation of human freedom and divine sovereignty, and how the existence of that free will in each possible world will result in improbable events occurring due to random chance, or luck.  

Is it good practice to wish someone good luck in finding a positive outcome in something beyond their control? I agree with my chastisers that it would be a better practice to pray and ask the Lord for an outcome than rely on luck. 

In a recent example, someone said they were trying a new doctor. I said: “Better luck this time.” 

There is of course a random element in the choosing, but the eventual outcome isn’t improbable at all. In this case, there was no element of luck involved, even if the positive outcome sought was beyond the control of the one seeking it. Since there was no improbable event that would occur through random chance, this was not a case of luck, and there would be no reason to wish someone good, or bad, luck in the outcome. 

But also in my defense, the off-hand statement was merely a pro forma way of wishing someone a desirable outcome. It was not meant to reveal a worldview based on eliminating the influence of God and nothing more than random chance. So, ya know… lighten up a little!