The Bible clearly states that faithfulness is important. I assume since this was asked in the relationships and marriage section that the answer should reflect that. The most clear example I can think of that shows that faithfulness is important is in Matthew 19. In Matthew 19:6, Jesus says "what God has joined together, let man not separate" (NIV). He also goes on to say in verse 8, that Moses allowed divorce certificates because of man's hard heart, not God's will. However, He goes on to say that it was not that way from the beginning and should not be that way. Therefore, I feel confident saying that the Bible shows great importance to faithfulness.
The next book in the Bible after Psalms is Proverbs.
The book before Proverbs in the Bible is the Book of Psalms.
proverbs
Ecclesiastes
None. The Bible order is for Proverbs followed by the Book of Ecclesiastes.
Proverbs
Proverbs 31 is the regularly quoted passage.
; Be not among winebibbers.... For the drunkard and the glutton shall come to poverty. Proverbs 23;20 -21
It says not to gossip 7 times, 6 in Proverbs and once in II Corinthians.
You can find the Proverbs in the Bible.
Ecclesiastes
Proverbs.