If you will not listen, if you will not take it to heart to give honor to my name, says YHVH Tsevaot, then I will send the curse upon you and I will curse your blessings. Indeed, I have already cursed them, because you do not lay it to heart.
Malachi 2:2

If you follow only the parts of religion that seem good to you or that you fully understand, then it will do you more harm than good. Sacrifice and worship are for both God and man, but only God has a complete understanding of them.

("I have a relationship, not a religion" is a self-refuting, religious statement.)