Pip spends an anxious, sleepless night at a hotel. In the morning, he goes to Walworth where Wemmick (speaking in code to avoid mixing Walworth and Little Britain) tells Pip he wrote the note after overhearing in Newgate Prison that Compeyson knows Provis is in London and has had Pip's apartment watched. Pip connects this news to the stranger lurking in his hallway a few days before.
Wemmick maintains his split personality even in the face of danger. The mysterious man in the hallway must have been Compeyson's spy. If Compeyson knows that Provis is in London, Provis is in danger.
Immediately after hearing the news, Wemmick enlisted Herbert to arrange a hiding place for Provis. Herbert has taken Provis to rent a room in Clara's building by the river. Pip has never been there because Clara does not approve of Herbert and Pip's friendship, thinking Pip a bad influence on Herbert's finances. Wemmick advises Pip to "lay hold of [Provis'] portable property" as soon as possible in order to protect it.
Herbert continues to prove himself a loyal friend, generously putting himself in danger in order to protect Provis. Pip's "gentlemanly" behavior of wasting money on luxury goods, which he thought would make him look good, has given him a bad reputation in Clara's eyes.