7. There is opportunity for doubt:

Three comments from Ellen White illustrate this thought:HPEGWW 18.3

While God has given ample evidence for faith, He will never remove all excuse for unbelief. All who look for hooks to hang their doubts upon, will find them. And those who refuse to obey God’s Word until every objection has been removed, and there is no longer an opportunity for doubt, will never come to the light….Unbelief strengthens as it is encouraged; and if men, instead of dwelling upon the evidences which God has given to sustain their faith, permit themselves to question and cavil, they will find their doubts constantly becoming more confirmed.—The Great Controversy, 527.

In her discussion of the prophetic role, she wrote:HPEGWW 19.1

Satan has ability to suggest doubts and to devise objections to the pointed testimony that God sends, and many think it a virtue, a mark of intelligence in them, to be unbelieving and to question and quibble. Those who desire to doubt will have plenty of room. God does not propose to remove all occasion for unbelief. He gives evidence, which must be carefully investigated with a humble mind and a teachable spirit, and all should decide from the weight of evidence.—Testimonies for the Church 5:675-676.

And one more on the opportunity for doubt:HPEGWW 19.2

If you refuse to believe until every shadow of uncertainty and every possibility of doubt is removed you will never believe. The doubt that demands perfect knowledge will never yield to faith. Faith rests upon evidence, not demonstration.—Testimonies for the Church 5:69.