1 Corinthians 15:33-34, 58

Be not deceived: evil communications corrupt good manners. Awake to righteousness, and sin not; for some have not the knowledge of God: I speak this to your shame.

Therefore, my beloved brethren, be ye stedfast, unmoveable, always abounding in the work of the Lord, forasmuch as ye know that your labour is not in vain in the Lord.