Zikr's importance

Therefore remember Me (by praying, glorifying,). I will remember you (i.e keep blessing you), and be grateful to Me (for My countless Favours on you) and never be ungrateful to Me.
Al Baqarah 152

And who are more unjust than those who forbid that Allâh's Name be glorified and mentioned much (i.e. prayers and invocations, etc.) in Allâh's mosques and strive for their ruin? It was not fitting that such should themselves enter them (Allâh's Mosques) except in fear. For them there is disgrace in this world, and they will have a great torment in the Hereafter.
Al Baqarah 114