Have you ever been pulled over for speeding and prayed, “Lord! I’ll never speed again if you just don’t let the officer give me a speeding ticket!”? We don’t think of that sort of prayer as a vow, but that’s exactly what it is.

While the Bible doesn’t prohibit vows, it does make clear that they are fraught with danger, “do not be hasty in your heart to utter anything before God” (Eccl. 5:2). Numbers 30 outlines the regulations for making vows, the key issue being that when one makes a vow to the Lord, “he must  not break his word but must do everything he said” (Num. 30:2). God does not require anyone to make a vow to Him, but He does expect the fulfillment of vows made. “It is better not to make a vow than to make one and not fulfill it” (v. 5). The Mosaic law treated rash or foolish vows to be a sin and made provisions for them (Lev. 5:4–5; see also Num. 30:6–8). God takes our words seriously.

In Ecclesiastes, the Teacher offers wise advice: “Let your words be few.” When we speak to God and to others, we should recognize God’s holiness: “God is in heaven and you are on earth so let your words be few” (v. 2). In the Lord’s Prayer, Jesus taught His disciples (and us) to use simple words that recognize who God is, ask Him for our needs, and trust Him to supply them (Matt. 6:9–13). Rather than piling up words to impress our friends or convince God to help us, Jesus said, we should approach God humbly and in faith (Matt. 6:6). God hears our words. Even so, He already knows what we need, so we should not make empty promises in a prideful attempt to bargain with the Creator of the universe.