Dickens made the phrase "Recalled to Life" purposefully intriguing and mysterious; A Tale of Two Cities was originally published in serial form, so Dickens heightened suspense in order to draw in as many readers as possible. The catch-phrase, "Recalled to Life," is first used in Chapter Two. Mr. Jarvis Lorry tells Jerry Cruncher a secret code for the "Mam-selle" at Dover. Jerry perceives the phrase as a "blazing strange message," but the reader soon deciphers its meaning as a reference to Doctor Manette's rescue from his eighteen years in prison. At the time of his release, Dr. Manette was mentally unstable and wasting away; his release gives him a new chance to reunite with his daughter Lucy and live peacefully.
I must say, due to mwestwood's exquisite answer, there is not too much to add; however, I can give a couple different tidbits. Of course, the term "recalled to life" is the carrier's, Jerry Cruncher's, message during his return on horseback from the Dover stage. Jerry's message reaches Jarvis Lorry right before he heads to France and is kind of a secret message.
The message is truly a mystery to Lorry. Even Jerry thinks it is a "strange message." It is only the reader that truly understands it and how it connects to "Mam-selle" at Dover. It is about Manette's rescue from his imprisonment at the Bastille. When he was let go, Manette was in poor condition, and his release gives him a new lease on life (especially to live in peace with his daughter, Lucie).
In conclusion, it is important to note that this message of "recalled to life" introduces one of the main themes of the novel: the dual nature of the body and the spirit. Note how Manette is bodily "recalled to life" from the Bastille after many years. Further, Sydney Carton is spiritually "recalled to life." He goes from a being a person of ill-repute (a simple barrister) to an upstanding citizen when he falls in love with Lucie Manette. This is proven when Sydney sacrifices his own life.
"Recalled to Life" is the return message that Jerry Cruncher, the carrier on horseback, returns with from the Dover stage one foggy night. On this stage is Mr. Lowry of Tellson's Bank, a representative who sojourns to Paris, but he has been told to "wait at Dover for Mam'selle." Jerry's urgent message reaches Mr. Lowry just before he embarks upon the boat to Calais, France, across the English Channel from which he will again take a coach.
It is a mysterious message, indeed, that Mr. Lorry gives Jerry to carry back to the bank--"recalled to Life," and he puzzles over its import as he rides back to London,
"No, Jerry, no!....It wouldn't do for you, Jerry, Jerry, you honest tradesman, it wouldn't suit your line of business! Recalled----! Bust me if I don't think he'd [Mr. Lowry] been a drinking!"
This phrase, "recalled to life," becomes a motif in Dickens's novel of dualities; moreover, it is involved in one of the ironic twists near the end of the novel as Jerry's secret profession to which he alludes in his remark on his ride to London becomes an important clue to solving one mystery. Also, two main characters are recalled to life: one physically is brought back to the world he once knew. Dr. Manette is released from the Bastille after fourteen years when the peasants stage a rebellion at the incipience of the French Revolution; the other is resurrected spiritually. Sydney Carton, a dissolute barrister, awakens his soul with love Lucie Manette and her family and maintains a friendship with the man of sterling character, Jarvis Lowry. Because of his great love for Lucie, he sacrifices his own life so that her husband Charles may live; thus, he is resurrected spiritually--recalled to eternal life--in his offering of himself.