Most of the questions we face in life are really quite simple to answer. We can appropriately and effectively respond to these questions with one of two one-word answers.

The first answer is “Yes.” A straightforward, basic affirmative. The second, not surprisingly, is “No,” as straightforward and basic a negative as “Yes” is an affirmative.

Many of the key decisions of our lives come down to our saying “Yes” or “No” at the right time. You’d think that wouldn’t be hard—after all, we have a 50-50 chance of being right, don’t we? The problem is that these decisions usually require more than the flip of a coin. We may appear to have an equal probability of being correct no matter what we choose, but the consequences are rarely, if ever, of equal weight. Our very future may turn entirely on the correct “Yes” or “No.”

Think of Aaron at the foot of Sinai. The great nation he and his brother Moses had led out of slavery in Egypt was restless. Moses had disappeared onto the mountain to converse with God. Their surroundings were unfamiliar and hostile. They didn’t know where they were headed or what would become of them. So they gathered around Aaron with a demand: “Come, make us gods that shall go before us” (Exodus 32:1).

Aaron had to answer. There were two choices: “Yes” and “No.” Aaron chose unwisely. He said “Yes” when he should have said “No.” He collected from the Israelites all of their golden earrings and melted them. With an engraving tool, he fashioned the image of a calf—a common object of worship in the country they had recently fled. And Aaron told the people, “This is your god, O Israel, that brought you out of the land of Egypt” (Exodus 32:4).

All Aaron had to say when the people confronted him was “No.” “No, I will not make you an idol to worship.” “No, I will not participate with you in wickedness.” “No, I will not turn my back on or blaspheme against the true and living God who delivered us from the hands of our oppressors.” But instead Aaron said “Yes,” and very nearly precipitated the destruction of the entire nation by an angry God, but for the pleading of Moses (Exodus 32:7-14).

Aaron had an excuse, of course. “You know the people,” he told Moses, “that they are set on evil” (Exodus 32:22-24). Aaron even tried to deny that he had actually molded the idol: “I said to them, ‘Whoever has any gold, let him break it off.’ So they gave it to me, and I cast it into the fire, and this calf came out.” Imagine that, Moses! I threw all these gold earrings in the fire and—what do you know—this golden calf just magically appeared! But neither God nor Moses were buying the tale Aaron was attempting to sell. They knew the truth—Aaron had said “Yes” when he should have said “No.”

How many lives have been ruined because someone said “Yes” to something—sexual immorality, intoxicating drugs, an opportunity to steal, a hunger for money, the enticements of the world that lead one away from God—when he or she should have said “No”? Ask David, or Samson, or Solomon, or Ananias and Sapphira, or Judas, or Demas. The replacement of one simple word for another at the right moment can avoid an unbearable agony of sin.

It’s also important to know when to say “Yes” when it might be tempting to say “No.” When Peter was asked three times on the night Jesus was betrayed, “Aren’t you with Him?” again and again he found himself saying “No,” showing himself both a liar and a cowardly turncoat. The bitter tears Peter shed when the rooster crowed—and that forsaken look cast his way by the Master he denied—could have been avoided by a plain, clear-spoken “Yes.” How many times have we been faced with a chance to affirm our faith in Jesus to others only to imply by our actions, “I do not know the Man”?

When God called Isaiah to prophesy, he could have said “No, Lord,” but instead replied, “Here am I! Send me” (Isaiah 6:8). Jeremiah was tempted to decline the Father’s summons (Jeremiah 1:4-8), but instead said “Yes.” Saul of Tarsus, called to follow the very Christ he persecuted, could easily have said “No, I will not obey,” but instead replied, “Lord, what do you want me to do?” (Acts 9:6). When challenged to answer for our faith, we must always be prepared to say “Yes” (1 Peter 3:15), even though we might think we’d rather say “No” and avoid being attacked, humiliated or ostracized.

Two little answers to so many of the huge questions: “Yes” and “No.” Jesus said, “Let your ‘Yes’ be ‘Yes,’ and your ‘No,’ ‘No.’ For whatever is more than these is of the evil one” (Matthew 5:37). Careful study of God’s word will train us to know which to use when (Hebrews 5:14).