Matthew 5:35

³³ Again, you have heard that it was said to the ancients, ‘Do not break your oath, but fulfill your vows to the Lord.’

³⁴ But I tell you not to swear at all: either by heaven, for it is God’s throne;

or by the earth, for it is His footstool; or by Jerusalem, for it is the city of the great King.

³⁶ Nor should you swear by your head, for you cannot make a single hair white or black.

³⁷ Simply let your ‘Yes’ be ‘Yes,’ and your ‘No,’ ‘No.’ Anything more comes from the evil one.

Do read the surrounding verses too, because the context often says more than a single verse.

Compare

BSB: or by the earth, for it is His footstool; or by Jerusalem, for it is the city of the great King.
KJV: Nor by the earth; for it is his footstool: neither by Jerusalem; for it is the city of the great King.
WEB: nor by the earth, for it is the footstool of his feet; nor by Jerusalem, for it is the city of the great King.
ASV: nor by the earth, for it is the footstool of his feet; nor by Jerusalem, for it is the city of the great King.
DARBY: nor by the earth, because it is [the] footstool of his feet; nor by Jerusalem, because it is [the] city of the great King.
BLB: nor by the earth, because it is the footstool for His feet; nor by Jerusalem, because it is the city of the great King.

ÅB: og ikke ved jorden, for den er hans fotskammel; og ikke ved Jerusalem, for det er den store kongens by.
OTB: eller ved jorden, for den er Hans fotskammel; eller ved Jerusalem, for det er den store Kongens by.
B1930: eller ved jorden, for den er hans fotskammel, eller ved Jerusalem, for det er den store konges stad.

Psalms 48:2
Beautiful in loftiness, the joy of all the earth, like the peaks of Zaphon is Mount Zion, the city of the great King.
Read in context
Malachi 1:14
“But cursed is the deceiver who has an acceptable male in his flock and vows to give it, but sacrifices a defective animal to the Lord. For I am a great King,” says the LORD of Hosts, “and My name is to be feared among the nations.
Read in context
Revelation 21:10
And he carried me away in the Spirit to a mountain great and high, and showed me the holy city of Jerusalem coming down out of heaven from God,
Read in context
2 Chronicles 6:6
But now I have chosen Jerusalem for My Name to be there, and I have chosen David to be over My people Israel.’
Read in context
Psalms 99:5
Exalt the LORD our God, and worship at His footstool; He is holy!
Read in context
Revelation 21:2
I saw the holy city, the new Jerusalem, coming down out of heaven from God, prepared as a bride adorned for her husband.
Read in context
Psalms 87:2
The LORD loves the gates of Zion more than all the dwellings of Jacob.
Read in context