In verse 7, Peter had challenged husbands about the possibility of their behaviour towards their wives being a reason for unanswered prayer. Perhaps they wondered if there were any other areas in life that could affect answers to one’s prayers. It is the case that answers to our prayers should be one of our biggest concerns. I remember once being asked to take a piece of paper and write down any specific answers to prayer that I had received around that time. The person who asked the question did not pursue his request, but it was a challenging one.
I suspect Peter is still focussing on the possibility of unanswered prayer in the verses we are looking at because he says in verse 12 that the Lord will either answer prayer or he will not. Therefore in the statements that precede verse 12 Peter is laying down the conditions for answered prayer, and I would say that is the particular blessing he has in mind in verse 9 when he informs his readers that they have been called to inherit a blessing. Peter explains the condition in two ways: first, he uses his own words in verses 8-9 and then he quotes from Psalm 34 in verses 10-12.
In passing we can observe the important place that Peter gives to the psalms as expressions of Christian experience. David wrote Psalm 34 in his own particular situation as he was guided by the Spirit. The psalmist had no idea that his words would later be very helpful to Christians living in Asia Minor, but the Spirit who guided him did. Neither did David know that over three thousand years later, millions of believers all over the world would get benefit from what he wrote in this psalm, but the Spirit who guided him did.
In verse 8 we have what is called a chiasm. This is a literary device that enables an author to stress a point and place beside it other important matters. The point that is stressed usually comes in the middle of the list. Here we have five items and we can number them: (1) unity of mind, (2) sympathy, (3) brotherly love, (4) a tender heart, and (5) a humble mind. Number 3 (brotherly love) is the central matter; then around it we can see that 2 and 4 are similar (the affections) as are 1 and 5 (the mind). So we can see, through this device, that answered prayer is dependent on brotherly love that shows itself affectionately on the one hand and humbly and unitedly on the other hand.