Christianity is ultimately Not about happiness, Nor the elimination of suffering

What is life "for" - it it to be happy - which implies a continual "timeless" state of bliss. 

If happiness is rooted-in the elimination of all suffering (which is the emphasis in some major religions); then there can be no needs, no desire, no "wanting"*. 

All Just Is, and what is, is good.  

Or else is life rooted in purpose? Purpose is dynamic, includes time; and purpose entails and some degree of dissatisfaction, yearning, wanting, desiring.

(Because if here-and-now was wholly satisfactory and sufficient, then there would be no reason to change it - no purpose.) 

Happiness (and the elimination of suffering) is in ultimate conflict with a life of purpose: one or other, but not both, can be the aim of spiritual life. They can't simultaneously be the aim. If we tried to conflate both in a unity, then one or other will - in actuality - be dominant over the other. 

So purpose is in-conflict-with the desire for a state of perfect happiness; and with the desire to eliminate all suffering - because purpose entails some degree of suffering. 

To live (always) with purpose, is always to experience some degree of dissatisfaction with here-and-now; in order to desire some, somewhat-different future state. 

Therefore the desire for happiness (including the elimination of suffering) is incompatible with purpose. 

This is part-of the incompatibility of, on the one hand, the many forms of oneness spirituality - of "Eastern" religion so-styled, yet actually far more widespread that the East, including being strongly, and from early, within Christianity) -- with, on the other hand, Christianity (properly understood).

Christianity is about purpose, ultimately. Therefore, not ultimately about happiness, nor about the elimination of suffering. 

What Christianity is about, is dynamic, purposive, taking place in-and through-time: it is about Love as the basis of creation. 

**

(But because Love has so often been defined in terms of a static state of perfect happiness, the dynamic purposive nature of Love - hence of creation - has become confused and/or occluded. To put is the other way about; there are two distinct ways of considering "Love" as the goal of existence: one is as a timeless, perfect-in-itself, blissful - and essentially impersonal - state; the other is as dynamic, purposive, creative - and essentially inter-personal.) 

*Note added: It could be said that Love (understood as participation in divine creation) is itself the ultimate happiness; and in a sense that would be correct - for those who choose to follow Jesus Christ. But it is not the ultimate happiness for everybody. It seems that for many people the highest happiness entails a changeless bliss. And there are others for whom the greatest gratification (if not exactly "happiness" entails that which Christians regard as evil - selfish gratifications of various kinds.