The Virus
The computer was infected. Connected to others in the network, it went about utilising their weaknesses and infecting them as well. They became compromised and vulnerable to further attacks.
Then I realised! Having spent hours tracking down the viruses and trying to clean up the computers, I saw the spiritual parallels. Like a network of computers, a community of people can be open to receiving both good things and bad things from one another. We need a firewall around us to protect us from attacks from the outside. But if we are already infected inside, we may be infecting one another in the group through their vulnerabilities.
We each need to have an antivirus program 'installed' in us - first to clean up the infections that are already in there, and repair us, and secondly to protect us from further infections. The spiritual viruses in our lives come about by wrong thinking and wrong beliefs, which make us malfunction. "Be transformed by the renewing of your minds" (Rom 12:2) - we need the pure truth of God's word in our lives (John 8:31-32) that can show up the problems (James 1:22-25), clean us (Eph 5:26), and protect us from further problems (Eph 6:13-14).
One of the viruses I've found in my life had been causing me problems. I was looking to others to make me happy and so if things went wrong, I felt down. Now I see that "rejoice in the Lord always" (Phil 4:4) means that I can find my strength and joy direct from God, in every moment. This is good protection from attack and viruses.