"But Jehovah is in truth God. He is the living God and the King to time indefinite. Because of his indignation the earth will rock, and no nations will hold up under his denunciation. This is what you men will say to them: 'The gods that did not make the very heavens and the earth are the ones who will perish from the earth and from under these heavens.' He is the Maker of the earth by his power, the One firmly establishing the productive land by his wisdom, and the One who by his understanding stretched out the heavens." - Jeremiah 10
Jehovah’s Witnesses, as the name implies, believe that Jehovah is the only true God.
On the last night of his life as a man Jehovah's foremost witness, Jesus Christ, expressed this truth in prayer to his heavenly father, saying to him: “This means everlasting life, their taking in knowledge of you, the only true God, and of the one whom you sent forth, Jesus Christ.”
According to Jesus God is a Spirit. (John 4:24 NIV) His place of dwelling is in another dimension, which Jesus referred to as the realms above earth, also known as heaven.
As the original Deity, Jehovah created all things, including Jesus Christ. Hence, Jehovah is the Creator. (The unique relationship between Jehovah and Jesus will be discussed in greater detail.) Being the only person in existence who did not have a beginning, Jehovah is called the King of eternity or King of the ages. (1 Timothy 1:17 Young's Literal Translation)
Having no limitations and no peer, Jehovah God is Almighty.
Jehovah is a person, a spirit person. Being a person means that God is an individual. God stated at Deuteronomy 6:4: "Listen, O Israel: Jehovah our God is one Jehovah." Being "one Jehovah" means that God is not three persons in one, as is commonly believed by trinitarians. Being a person, God has a personality. Besides being all-powerful, eternal and the source of all knowledge and wisdom, God's dominate personality trait is love. Jehovah is the very personification of love. He is said to be abundant in mercy and loving kindness. Jehovah is also a lover of justice. God's personality is reflected in humanity. That is because God originally created man in his image. Although, due to fallen human nature God's image is not reflected in humanity as God intended, still, the fact that mankind possess and values such qualities as love, kindness, mercy and justice testifies to God's character.
Jehovah's Witnesses believe that it is God's purpose to rehabilitate mankind, so as to uplift humanity out of its sinful dying condition.
The God who sponsored the writing of the Bible has a distinctive personal name. In Hebrew, the language in which the so-called Old Testament was primarily, originally written, the personal name of God was written using for Hebrew consonants that correspond to YHWH. The four Hebrew letters are known as the Tetragrammaton. The Tetragrammaton may be thought of as a sort of abbreviation. The reader of Hebrew was expected to know which vowel sounds were to be used with each consonant to form syllables. Through disuse it cannot be definitively determined which vowels were used. Hence, the correct pronunciation is uncertain. That being said, although some scholars prefer Yahweh, the name Jehovah is in keeping with the English pronunciation of other Hebrew names. For that matter, there are dozens of renderings of YHWH in various languages, Latin-based languages and otherwise, that use similar spelling as the English.
The importance of knowing and honoring God's name cannot be understated. According the the ancient prophecy of Joel, during the cataclysmic end of the present system everyone who calls upon the name of Jehovah will be saved. (Joel 2:32 - American Standard Version)
It is also God's intention to have his name declared in all the earth. In this Jehovah's Witnesses have been instrumental. The Watchtower Society has published the name of God and his purpose in 400 languages. But that is merely preliminary. Jehovah will ultimately force the peoples of the world to recognize his name and supremacy. “Therefore here I am causing them to know; at this one time I shall cause them to know my hand and my mightiness, and they will have to know that my name is Jehovah.” - Jeremiah 16:21