They have set themselves a goal in the achievement of which they compete and vie with one another. That goal is to do good works. For all these reasons they merit this testimony from on high that they belong to the righteous. They also have the promise which never fails that they will never be denied their reward. The verse adds that Allah, who is aware of all things and all people, knows that they belong to that special group of people who genuinely fear Him.
Deeds are the crop of faith.
Unless the faith is pristine pure the deeds cannot be virtuous. This picture is raised in front of the eyes of those who wish to have a similar testimony and a similar promise. They have only to follow the same line and adopt the same attitude. They will then find its light spreading over the limitless horizon in their lives. On the other side stand the disbelievers who will not benefit by their possessions or by their children.