‘Salute one another with a kiss of love. Peace be to you all who are in Christ.'
This is not a call for formalities, but a plea for oneness. They are to reveal their chaste love for one another by a meaningful symbol of love rather than with a pretence that has no meaning. ‘By this will all men know that you are My disciples, if you have love one to another' (John 13:35). Note that it is not sufficient to formally kiss one another's cheeks, it must be a kiss of genuine love.
‘Peace be to you all who are in Christ.' Peter finishes on this sublime thought. We who are His people are ‘in Christ'. That is why we will be carried safely through the billows of life borne up in Him as the Ark of God (1 Peter 3:20), with a certain landing in His heavenly Kingdom. And that is why we can enjoy His peace.