In a statement urging Israel to abandon idolatry and return to the Lord (Jehovah) Samuel says:
And Samuel spake unto all the house of Israel, saying, If ye do return unto the LORD with all your hearts, then put away the strange gods and Ashtaroth from among you, and prepare your hearts unto the LORD, and serve him only: and he will deliver you out of the hand of the Philistines. - 1 Samuel 7:3
This theme of serving God only as illustrated by forgoing the service of idols or false prophets and returning to the service of Jehovah God is oft repeated in Scripture:
Thou shalt not hearken unto the words of that prophet, or that dreamer of dreams: for the LORD your God proveth you, to know whether ye love the LORD your God with all your heart and with all your soul. Ye shall walk after the LORD your God, and fear him, and keep his commandments, and obey his voice, and ye shall serve him, and cleave unto him. - Deuteronomy 13:3-4
Now therefore fear the LORD, and serve him in sincerity and in truth: and put away the gods which your fathers served on the other side of the flood, and in Egypt; and serve ye the LORD. And if it seem evil unto you to serve the LORD, choose you this day whom ye will serve; whether the gods which your fathers served that were on the other side of the flood, or the gods of the Amorites, in whose land ye dwell: but as for me and my house, we will serve the LORD. - Joshua 24:14-15
This theme is picked up by Jesus in responding to the temptations of Satan in the desert and recorded almost identically in both Matthew and Luke:
And saith unto him, All these things will I give thee, if thou wilt fall down and worship me. Then saith Jesus unto him, Get thee hence, Satan: for it is written, Thou shalt worship the Lord thy God, and him only shalt thou serve. - Matthew 4:9-10
If thou therefore wilt worship me, all shall be thine. And Jesus answered and said unto him, Get thee behind me, Satan: for it is written, Thou shalt worship the Lord thy God, and him only shalt thou serve. - Luke 4:7-8
It is interesting to note how, in responding to the temptation to worship Satan, Jesus links worship and service of God together. To worship an idol is to serve that idol and to serve a false God is to worship that God. Jesus categorically declares (and also echoes all of God's revelation to us) that only God, Jehovah God, the Lord Almighty should be worshiped and served.
Servants, obey in all things your masters according to the flesh; not with eyeservice, as menpleasers; but in singleness of heart, fearing God: And whatsoever ye do, do it heartily, as to the Lord, and not unto men; Knowing that of the Lord ye shall receive the reward of the inheritance: for ye serve the Lord Christ. - Colossians 3:22-24
And in another place, regardless of what is meant by the strange Chaldean word mammon, Jesus says that two different masters (one God and one non-God) cannot both be served:
No man can serve two masters: for either he will hate the one, and love the other; or else he will hold to the one, and despise the other. Ye cannot serve God and mammon. - Matthew 6:24
My question, therefore is, given Jesus exhortation to serve the Lord thy God only and the apostle Paul's reminder that it is the Lord Christ whom Christians serve: Whom do Jehovah's Witnesses serve?