As a child, on Christmas eve, you were excited about the gifts Santa Clause had left for you. You thought that they were gifts from heaven!
So as you grew matured, you realise that what you thought to be truth is no longer a truth. This applies to many aspects of your life as well as to many Spiritual Truths.
Therefore, when you hear something, do not make any judgement. If it is not important, ignore it. But if it is important, analyse it properly and throughly before you conclude anything. For what you hear can be just a partial or one level of Truth.
Also when you think what you know is the ultimate Spiritual Truth, be aware that there are higher levels of truth you will discover when you Spiritually advance. Never be struck with what you know or hear. For, Truth is Dynamic.