"The rNWT replaces "kyrios" (Lord) with "Jehovah" in translating Romans 14:8 as follows:
"For if we live, we live to Jehovah,*+ and if we die, we die to Jehovah.* So both if we live and if we die, we belong to Jehovah."
But note what the very next verse (Romans 14:9) says:
"For to this end Christ died and came to life again, so that he might be Lord over both the dead and the living."
It is very clear from the wording of verse 9 that Kyrios (Lord) mentioned in verse 8 is referring to Jesus and should not be replaced with "Jehovah", because verse 9 is a justification of the idea mentioned in verse 8 as evidenced by the use of the phrase "For to this end . . ." and then going on to refer to christ being kyrios (Lord) over both the dead and the living.
Now notice how the two verses make much better logical sense if kyrios is left as "Lord":
"For if we live, we live to the Lord,*+ and if we die, we die to the Lord.* So both if we live and if we die, we belong to the Lord.*+ 9 For to this end Christ died and came to life again, so that he might be Lord over both the dead and the living."
Do you see that? Both verses refer to life and death and both verses refer to one who is Lord of the dead and the living. Verse 9 is actually a justification or explanation of what is stated in verse 8. Since verse 9 explicitly identifies the Lord being referenced as christ then it is obvious that the Lord being referred to in verse 8 is christ and not Jehovah."
Taken from my Y!A question