Peter uses the word “inexpressible” to indicate that he cannot find words to describe what this joy is like. Given that this joy is rooted in heavenly realities, it is really no surprise that earth’s vocabulary (and human imagination) is too limited to capture the deep colours of Christ-centred joy. Even so, those who are born again receive a taste of this joy that those not born again simply can’t begin to fathom.
8 Though you have not seen him, you love him. Though you do not now see him, you believe in him and rejoice with joy that is inexpressible and filled with glory,