New Revised Standard Version
But Ittai answered the king, “As the LORD lives, and as my lord the king lives, wherever my lord the king may be, whether for death or for life, there also your servant will be.”

Contemporary English Version
Ittai answered, "Your Majesty, just as surely as you and the LORD live, I will go where you go, no matter if it costs me my life."

New American Bible
But Ittai answered the king, “As the LORD lives, and as my lord the king lives, your servant shall be wherever my lord the king is, whether for death or for life.”

Douay-Rheims Bible
And Ethai answered the king, saying: As the Lord liveth, and as my lord the king liveth: in what place soever thou shalt be, my lord, O king, either in death, or in life, there will thy servant be.

And Ethai answered the king, saying: As the Lord liveth, and as my lord the king liveth: in what place soever thou shalt be, my lord, O king, either in death, or in life, there will thy servant be.

As the Lord

1 Samuel 20:3 And he swore again to David. And David said: Thy father certainly knoweth that I have found grace in thy sight, and he will say: Let not Jonathan know this, lest he be grieved. But truly as the Lord liveth, and thy soul liveth, there is but one step (as I may say) between me and death.

1 Samuel 25:26 Now therefore, my lord, the Lord liveth, and thy soul liveth, who hath withholden thee from coming to blood, and hath saved thy hand to thee: and now let thy enemies be as Nabal, and all they that seek evil to my lord.

2 Kings 2:2,4,6 And Elias said to Eliseus: Stay thou here, because the Lord hath sent me as far as Bethel. And Eliseus said to him: As the Lord liveth, and as thy soul liveth, I will not leave thee. And when they were come down to Bethel, . . .

2 Kings 4:30 But the mother of the child said: As the Lord liveth, and as thy soul liveth, I will not leave thee. He arose, therefore, and followed her.

surely

Ruth 1:16,17 She answered: Be not against me, to desire that I should leave thee and depart: for whithersoever thou shalt go, I will go: and where thou shalt dwell, I also will dwell. Thy people shall be my people, and thy God my God. . . .

Proverbs 17:17 He that is a friend loveth at all times: and a brother is proved in distress.

Proverbs 18:24 A man amiable in society, shall be more friendly than a brother.

Matthew 8:19,20 And a certain scribe came and said to him: Master, I will follow thee whithersoever thou shalt go. . . .

John 6:66-69 After this, many of his disciples went back and walked no more with him. . . .

Acts 11:23 Who, when he was come and had seen the grace of God, rejoiced. And he exhorted them all with purpose of heart to continue in the Lord.

Acts 21:13 Then Paul answered and said: What do you mean, weeping and afflicting my heart? For I am ready not only to be bound, but to die also in Jerusalem, for the name of the Lord Jesus.

2 Corinthians 7:3 I speak not this to your condemnation. For we have said before that you are in our hearts: to die together and to live together.