When it comes to speculating, however, I’m not so sure that answer is clear. We certainly know planning is okay; even encouraged. It’s throughout the Proverbs. Every bit of planning I know of involves a certain amount of planning and even risk-taking. Then there’s the Jesus’ parable of the talents. In that story the master criticizes the one who did nothing with the talent he received by saying, “you should have at least put it in the bank where it could draw interest”. Investing for interest is certainly a speculative world. Also coming to my mind is the whole book of Revelation and where Jesus talks about the coming Kingdom. When my mind goes there I’m many times speculating, but it’s a healthy speculation. I’m dreaming of an eternity with the God who I love so much. (I hope that illustration makes sense. I’m dealing here with the word itself speculation.) So there is certainly a case to be made for speculation that is okay for the believer. (Again, that’s in my opinion.) Speculation to me is a certain organized thinking process that centers on a certain subject. Take a career like financial planning or military strategist (both of which I know good Christian people in the fields). They are centered for the most part on a certain amount of speculation. I don’t think that process alone is wrong even for the believer.
I think the key is where our heart is. Proverbs 4:23 says that we are to protect the heart against everything else. One way I’d say this is to borrow off another Biblical concept of grieving. We don’t speculate like the rest of the world. If speculating causes worry, then of course it would be wrong for us to engage in it. I got so caught up in politics during a season of my life than in order to protect my heart I stopped reading the paper. I still don’t read as much of it as I used to, but I’m careful not to get saturated with it to the point that it causes me to get worried or angry in an unhealthy way. If it starts to impact my family-time, for example, I know I’ve gone too far.
On the other hand, if speculating causes preparation, planning, dreaming, and even risk-taking in areas that are not sinful and God-honoring, then I think it is okay for a believer to speculate on what might occur. Of course, in the end, God is fully in control, our trust is fully in Him, and He will work all things for good. In the meantime, we do the best we can with the minds and experiences He gives us to love Him and others, while living in the world, but not of the world.