The Thing that we (all) most need to do is to develop our consciousness by learning and practicing primary thinking.
Nothing is more important and everything Good (including, ultimately, our ability to be Christian) depends on it - and this is why purposive supernatural evil is incrementally shaping the world towards the prevention of primary thinking.
We must get in touch with reality directly (by primary thinking) by learning and actively, consciously attaining direct knowledge of the universal realm of reality.
At present, in mainstream modern life, we know the world only 'secondhand' - we know only a virtual and constructed world - and have been persuaded that this secondhand world is the only metaphysical reality. We ignore/ violently-reject even the possibility of first-hand knowledge.
Our 'facts' are increasingly only what is perceived by our senses (and tools/ machines/ computers fed by sensory data) - and these perceptions (the 'basic data') are increasingly those selected and invented by the mass media, bureaucratic propaganda and official regulations.
Our concepts (by which we make sense of these 'facts') are less-and-less those which are universal and eternal; and more-and-more those which are absorbed from socialisation, education and the conditions of modern living. And these concepts increasingly derive-from, are controlled-by, the mass media, bureaucratic propaganda and official regulations.
In sum, our secondhand world is globally controlled and - because of our false metaphysical assumptions - has become not just primary but the sole world. Insofar as the world of primary reality still exists in our lives, it is systematically denied validity - written-off as childish, crazy, arbitrary, repressive, subjective...
Modern life has become almost-wholly virtual, external, secondhand and controlled - but the fact is obscured by the pretence that only such perceptual, conjectural, changeable, contingent and authority-validated hypotheses are rigorous.
This situation is why there is no higher priority than each of us connecting with primary reality - by means of primary thinking, and recognising the ultimate authority of direct knowing derived from primary thinking.
Christianity without such development of consciousness and renewal of metaphysics cannot suffice; because we will be unable to evaluate, think or reason about Christianity using only the assumptions, 'facts' and conceptual tools that are all that modern life allows us.