Only be thou strong and very courageous, that thou mayest observe to do according to all the law, which Moses my servant commanded thee: turn not from it to the right hand or to the left, that thou mayest prosper whithersoever thou goest. This book of the law shall not depart out of thy mouth; but thou shalt meditate therein day and night, that thou mayest observe to do according to all that is written therein: for then thou shalt make thy way prosperous, and then thou shalt have good success.
Joshua 1:7-8
Many people today treat the truth like a cafeteria buffet. They pick and choose the things that look appealing and that they think they will enjoy, and they leave the rest behind. That is not the way God's truth works. It is all part of a unified whole. It is all true, and it must all be taken as true. John Newton wrote, “The Word of God is not to be used as a lottery; nor is it designed to instruct us by shreds and scraps, which, detached from their proper places, have no determinate import; but it is to furnish us with just principles, right apprehensions to regulate our judgments and affections, and thereby to influence and direct our conduct.”
We are not equipped or qualified to evaluate which parts of the Bible we should believe and which we should discard. That puts us in a position that can only rightfully be held by God. Instead we are to take the whole of God's truth, read it, study it, memorize it, meditate on it, and follow what it says. Whether the truth is widely accepted or believed only by a few, it is still truth. And it is all truth. Paul was able to testify that his ministry was not based on picking and choosing, but believing it all. He said, “For I have not shunned to declare unto you all the counsel of God” (Acts 20:27).