There was a time when you could say that God may have been without a reliable organization or witness. When Adam and Eve sinned and there was no one else yet living would be one such time and just before the flood when only Noah and his immediate family were viewed as worthy of surviving that time period.
Before the modern day organization of Jehovah's witnesses existed there were people that had God;s favor. These persons would have been found in the religions of Christendom. The early members of the International Bible Students [as Jehovah's Witnesses were then known] recognized such ones. When they too began to associate with those Bible Students they did not get re-baptized. It was not until a later date that a need for that was determined.
The formation and progression of Jehovah's Witnesses over the years has been a gradual process. In the early years there were many things for instance that were not all that different from the rest of the religions claiming to be Christian.
God judges hearts and he can choose to overlook things or he can choose not to. It may depend on time and circumstance. For instance in ancient Israel he allowed for polygamy. That doesn't mean that it was something he approved of.
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Since God’s original standard for mankind was for the husband and wife to become one flesh, polygamy was not intended, and it is prohibited in the Christian congregation. Overseers and ministerial servants, who are to set the example for the congregation, are to be men having not more than one living wife. (1Ti 3:2, 12; Tit 1:5, 6) This is in harmony with what true marriage is used to picture, namely, the relationship of Jesus Christ and his congregation, the only wife possessed by Jesus.—Eph 5:21-33.
As was the case with divorce, polygamy, while not God’s original arrangement, was tolerated until the time of the Christian congregation. Polygamy had a start not long after Adam’s deflection. The first Bible mention of it is concerning a descendant of Cain, Lamech, of whom it says: “[He] proceeded to take two wives for himself.”
If you ask me, this practice was a direct example of haw man dominated woman as was mention at Genesis 3:16, "To the woman he said: “I shall greatly increase the pain of your pregnancy; in birth pangs you will bring forth children, and your craving will be for your husband, and he will dominate you.” It was not God's will than man should dominate woman but that the man should cherish his wife and treat her with honor but the scripture in Genesis shows that one of the results of sin would be that man would dominate woman. Thus you reap what you sow and polygamy was one of the ways woman was dominated by man.
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So too just as imperfect Israel was used for thousands of years to represent God's chosen people, all those who practiced some form of Christianity were similarly viewed as being within the fold so to speak. Yet just as the time came when Jehovah no longer recognized ancient Israel as his chosen people when they rejected Christ he no longer recognized the religions of Christendom after they rejected Jesus when he took kingdom power in 1914, which is the time that we believe God's kingdom was established in the heavens and Satan was thrown down to the earth. [See Revelation 12:12 & Acts 2:34]
The time came in this modern "time of the end" for God to take out of the nations a people for his name and to re-establish true worship. (Acts 15:14) Daniel 12:4 says, “And as for you, O Daniel, make secret the words and seal up the book, until the time of [the] end. Many will rove about, and the [true] knowledge will become abundant.”
So if what the Bible says is true and the true knowledge would become abundant in the time of the end then at that time God would hold people to a higher standard and they would be judged on whether or not they accepted or rejected the message connected with that true knowledge. We believe and are convinced that we have the truth so much so that we refer to our beliefs as "the truth" even as the first Christians referred to their way of living as "the way".