Sermon: To Tell the Truth
Scripture: Matthew 5:33-37
In this week’s lessons, we see the importance of telling the truth, and of the need to cultivate a godly heart and mind.
Theme: Man’s Oaths
When God appeared to Abraham and passed between the pieces, what did God say? He said, “Know of a surety,” and He went on to outline the next five hundred years of Israel’s history. Think of that phrase—“know of a surety.” It means that God does not want a man to know a thing halfway. He does not want us to be doubtful about our salvation or any of His promises. And so, being able to swear by none higher, He swears by Himself. Thank God it is so! If any part of salvation depended upon us, we would soon be quaking with fear and trembling with doubt. But since all rests on the oath of God, we can be certain.
As we go on throughout the Bible we find God swearing never to destroy the earth again by flood (Gen. 9:9-11), to send a redeemer (Luke 1:68, 73), to raise His Son from the dead (Ps. 16:10; Acts 2:27-31), to preserve and eventually bless Israel (Is. 49:15-18), and other things. Why does God do it? The author of Hebrews says, “So when God desired to show more convincingly to the heirs of the promise the unchangeable character of his purpose, he interposed with an oath, so that through two unchangeable things [that is, the word of God and the oath of God] in which it is impossible that God should prove false, we who have fled for refuge might have strong encouragement to seize the hope set before us. We have this as a sure and steadfast anchor of the soul” (Heb. 6:17-19).
Now I know that someone will be saying, “Well, if it’s true that the taking of oaths is approved throughout the Bible, why is it that the Lord Jesus commands us: ‘Swear not at all’?” The answer is that in Jesus’ day the taking of oaths had been greatly abused, and it had come about that the practice was actually weakening the cause of the truth rather than contributing to it. 
In Palestine in the time of Jesus, there were two unsatisfactory things about the taking of oaths. The first was what William Barclay calls frivolous swearing, that is, taking an oath when it was neither necessary nor proper. People who did this swore by their life or their head (or whatever it might be) for almost nothing. The result was that even the most solemn statements appeared to be on this level also. It was exactly as if a servant who lived in the household of an honorable state official should go around talking about the honorable house, the honorable chair, the honorable mop, the honorable dishpan, and so forth. His speech would then have much less meaning when he called the lord of the house “your honor.” In opposition to this, Jesus often insisted (as many of the rabbis did also) that the use of an oath to substantiate a simple statement was wrong. 
Study Questions:

What examples from the Bible do we have of God promising to do or not do something? Can you think of other examples besides those mentioned in today’s study?
Why does the writer of Hebrews say God uses an oath?
What is the first abuse against which Jesus is reacting in the Sermon on the Mount?

Reflection: How do people today use oaths in an inappropriate way?
Key Point: If any part of salvation depended upon us, we would soon be quaking with fear and trembling with doubt. But since all rests on the oath of God, we can be certain.

Study Questions
Tagged under
More Resources from James Montgomery Boice

Subscribe to the Think & Act Biblically Devotional

Alliance of Confessional Evangelicals

About the Alliance

The Alliance is a coalition of believers who hold to the historic creeds and confessions of the Reformed faith and proclaim biblical doctrine in order to foster a Reformed awakening in today’s Church.

Canadian Donors

Canadian Committee of The Bible Study Hour
PO Box 24087, RPO Josephine
North Bay, ON, P1B 0C7