Galations 6:9 – And let us not grow weary in doing good, for in due season we will reap, if we do not give up.
When we do things for the Lord, be it a ministry or acts of service, we will run into opposition and resistance from the evil one.  Do not be discouraged nor lose heart in the good works you do unto the Lord.  Instead, strive to do good to those around you and never give up was the Lord has called you to accomplish.  He will see you through to the end.