How can you tell whether it's God speaking to you or the devil? Last year, I had a very strong feeling that I ought to do something, and I thought God must be telling me to do it. But it turned out to be very wrong, and now I think it must have been the devil. But how could I have known? — Mrs. B.McF.
As you look back, what made you decide God was leading you? I don't know the answer to that, of course, but I suspect the reason was an emotional conviction on your part—a strong feeling that this path must be right.
But our feelings and emotions can be tricky, and they can deceive us—especially if we depend on them alone for making a decision. God has given us our emotions, and they are important—but God also has given us our mental abilities, and when we face a decision, we also need to look at it carefully and logically. Part of discerning God's will is to ask Him to help us see all sides of an issue—sometimes with help from others we trust.
Emotion and intellect aren't enough, however. When we face a decision, we need to do it prayerfully, trusting God to lead us. We also need to do it in light of God's Word, the Bible. God will never lead you to do something that is not in accord with the Bible—never.
The Bible says, "Trust in the Lord with all your heart and lean not on your own understanding; in all your ways acknowledge him, and he will make your paths straight" (Proverbs 3:5-6). Make sure of your commitment to Christ, and then submit every decision you face to Him. When we sincerely want God's will above all else, He will help us know what is right.