He encouraged the brethren to be hospitable. This love in training is not something that is instantly developed. Peter was one of the apostles sent to prepare the Passover feast. For the administration of this service not only supplieth the want of the saints, but is abundant also by many thanksgivings unto God. When brethren feel welcome, it can counteract the feeling of loneliness.
Hospitality can relieve suffering and strengthen the bond of brotherhood.
In the atmosphere of hospitality, matters of the heart and the truth can be discussed. Comfort and encouragement as well as mutual support and correction will abound in such arrangements. What brethren say can make a difference. It can counter the adverse affects of false teachings and this is what Peter was warning the brethren about in his epistle. Many false teachings could have been nipped in the bud early on had discussion and dialogue been encouraged.