The phrase itself can refer to any desires of the flesh that are contrary to the will and word of God (Galatians 5:19–21). More specifically in relation to Peter, the phrase can describe any desire (or conduct) that contradicts the blessed identity Peter has described in 1 Peter 1:3 – 2:10. That is the sense of the term passions
as Peter uses it in 1 Peter 1:14, 1 Peter 4:2–3. Narrowing the term down still further in relation to its place in the present passage (though without excluding any of the above), we could perhaps understand that the specific passion of the flesh Peter’s readers must be alerted to is the inner revulsion every person has to being different, that is, to being “sojourners and exiles.” Nobody likes to stick out, and so every person is tempted to conform to the (perceived) expectations of the herd.
11 Beloved, I urge you as sojourners and exiles to abstain from the passions of the flesh, which wage war against your soul.