The religious concept that has been latched onto and labeled Doctrine has nothing in common with the teaching — or doctrine — of Christ. False doctrines are not merely un-Biblical or non-Biblical teachings that need to be countered with Biblical teachings or right thinking (even though I do see a great need in this area). You see, the thing that makes them false is not the lack of technical rightness, but is often the insistence upon technical rightness — instead of upon life. [The word foundations — which is a good word — could be used in this manner as well, so it’s not the word I have a problem with.]
This does not mean the problem with doctrines is the accuracy of the stated truth, but is instead the underlying demand that our life in Christ consists of a right set of beliefs to attain to and agree upon. Do you suppose I don’t realize that I have many teachings or doctrines all throughout my own writings? Of course I do. And if I do realize this, and I still say what I do about doctrines, then I must be targeting something other than the idea of simple truths, wouldn’t you think?
As an example, let’s take the truth of Abraham that you posted. The Pharisees demanded this truth be adhered to — and yet because it was only part of their doctrinal structure they were able to quote it, throw it in the face of Jesus and his disciples, and somehow use it to set themselves above others. Was the truth of God’s promise to Abraham the problem? Of course not. Then what was the false teaching of the Pharisees regarding Abraham? Wasn’t it simply that they viewed this truth according to their fleshly reasonings? They didn’t need more Biblical truth or even a more accurate view of Biblical truth — they needed the life of God. This is my distinction regarding doctrine.