Why should Christians attend church regularly
Hebrews 10: 23 to 25 is pretty specific:
23 Let us hold fast the profession of our faith without wavering; (for he is faithful that promised;)
24 And let us consider one another to provoke unto love and to good works:
25 Not forsaking the assembling of ourselves together, as the manner of some is; but exhorting one another: and so much the more, as ye see the day approaching.
Also, 1 Corinthians 12 is pretty good as well (link)