In the beginning, God created man in his own image. Ever since, man has tried to reverse the process. People imagine what they wish God were, instead of accepting the self-description he has given in his word.
Consider these words from Samuel Rutherford,
“Ye may yourself ebb and flow, rise and fall, wax and wane; but your Lord is this day as he was yesterday; and it is your comfort that your salvation is not rolled upon wheels of your own making, neither have ye to do with a Christ of your own shaping.”
The gods people have made up are false gods, powerless gods, worthless gods. It is vain to worship something we have created -- whether with our hands or with our imaginations. But all too often that is exactly what we are doing.
What is the nature of God? What is his attitude toward sin? What does he demand of us? Under what circumstances will he accept us into his presence? Under what circumstances will he banish us from his presence?
What we think in regard these questions must align with what he has said in his word, or we are worshipping a god of our own making rather than the true Father of Jesus Christ. One might as well fall down and worship a block of wood carved by his own hands as to worship a god of one’s own imagination.
If you cannot cite book, chapter, and verse for what you believe about God, there is a good chance that what you believe is nothing but the vain product of your own mind. We do not have to do with a Christ of our own shaping. We will not answer to the god of our imagination. Now is the time to leave our daydream gods and get to know the real one. In eternity it will be too late.
Thus says the Lord of hosts: "Do not listen to the words of the prophets who prophesy to you, filling you with vain hopes. They speak visions of their own minds, not from the mouth of the Lord. They say continually to those who despise the word of the Lord, 'It shall be well with you'; and to everyone who stubbornly follows his own heart, they say, 'No disaster shall come upon you.'" (Jeremiah 23:16-17, ESV)