When asked about the importance of assurance in the Christian life, Douglas Campbell, a brilliant and faithful biblical scholar, responds in this way:
“One of the things that we are delivered from is introversion and narcissism. And God doesn’t want us wandering around worrying about ourselves. God wants us turned out towards the rest of the world; there are people out there that need help. We are the ones that are supposed to help them. Unfortunately, we have generated theological models that have created such anxiety that we’ve got classrooms full of anxious Christians and they’re not really confident that God is working in their lives and is able to work in the lives of others. So, I really do encourage my students… ‘If you confess with your mouth that Jesus is Lord; believe in your heart that God raised Him from the dead, then you will be saved’. You’re there, bro. Stop worrying about yourself and get out there and visit some prisons”
I have found that when I spend time caring, loving, and serving others as Christ commands us to do, you don’t have time to be distressed about whether or not you’re in the kingdom. Get out there and do the good works that God has called you to do! Assurance will take care of itself.
(This was transcribed by me from a debate between Douglas Campbell and Douglas Moo; https://www.youtube.com/watch?v=KlujS-fH8R4 (1:56:03)