Isaiah 66:1 states, Thus says the LORD: "Heaven is My throne, And earth is my footstool. Where is the house that you will build Me? And where is the place of My rest? (Emphasis mine.)
Let's look at James 5:12 which repeats the idea behind this passage and gives us straight-forward instruction for proper speech. But above all, my brethren, do not swear, either by heaven or by earth or with any other oath. But let your "Yes" be "Yes," and your "No," "No," lest you fall into judgment.
More Scripture on the importance of not swearing:
"And you shall not swear by My name falsely, nor shall you profane the name of your God: I am the LORD." Leviticus 18:12
"When you make a vow to the LORD your God, you shall not delay to pay it; for the LORD your God will surely require it of you, and it would be sin to you. 22But if you abstain from vowing, it shall not be sin to you. That which has gone from your lips you shall keep and perform, for you voluntarily vowed to the LORD your God what you have promised with your mouth.
Deuteronomy 23:11 (Emphasis mine).
In our everyday communication, we should never swear by or to God, nor by ourselves or anything or anyone else created by Him. Only God can swear by Himself as He is the Highest and there is none greater than Him. As believers, our word should be our bond. We should not have to pursuade others to believe us by swearing. We should not risk sinning by not following through with an oath we have made.
37But let your 'Yes' be 'Yes' and your 'No,' 'No.' For whatever is more than these is from the evil one."
As we have already noted above, this warning was also given in the book of James.
A final word in closing. This can apply to all areas of our speech.
Colossians 4:6, Let your speech always be with grace, seasoned with salt, that you may know how you ought to answer each one.
