Ephesians 4:27-28

and do not give the devil a foothold.

(v27, NIV)

A climber of some sort I would imagine climbs. A mountain climber would climb a mountain and a rock climber would climb rocks. These climbers would proceed upward along whatever they are climbing. The devil is similar to a climber because in a sense, he climbs each and every one of us. Climbers require places in which they can grab on to or step on in order to continue climbing whatever they are climbing; this is assuming that they are not using special methods or tools and are just climbing with their arms and legs. So, if these handles or footholds do not exist, it is extremely difficult for the climber to climb whatever he or she is climbing. In the same way, if the devil climbs us, he requires places to grab or step on in order to climb us. We should not make it easy for him by providing him with footholds.

Footholds are anything that makes it easy for the devil to climb us. The devil climbs and masters us through temptation and sin. Allowing the sun to go down while you are still angry will provide the devil with a convenient foothold. Do not give the devil a foothold by doing things like that.

He who has been stealing must steal no longer, but must work, doing something useful with his own hands, that he may have something to share with those in need.

(v28, NIV)

Your former way of life may have included stealing, but you shouldn't continue stealing. In the same way, your former way of life may have been filled with anger and allowing the sun to go down while still angry. This is not how you are to live and this is not the way of your new self. The follower of Jesus Christ puts off his old self which contains his habits of stealing. After putting off the old self, he or she will put on a new self. The new self includes working hard and doing something useful. Those who steal take from others, but one who is wearing the new self should share with others. In order to share with others, you need something to share. Therefore, it is necessary to have something in order to share with others.

If you don't have anything, it doesn't mean you aren't following what Paul is instructing here. Maybe you don't have anything because you're sharing it with others as soon as you get it. Also, working hard doesn't mean amassing a whole bunch of stuff for your own greed and pleasure. The point is to allow you to share with those in need.