1 Thessalonians 5:16 – 22
New International Version (NIV)
16 Rejoice always, 17 pray continually, 18 give thanks in all circumstances; for this is God’s will for you in Christ Jesus.
19 Do not quench the Spirit. 20 Do not treat prophecies with contempt 21 but test them all; hold on to what is good, 22 reject every kind of evil.
From BibleGateway.com: http://www.biblegateway.com/passage/?search=1+thessalonians+5.16-22&version=NIV