The two thefts in Silas Marner hold a lot of significance to the novel. Each of the thefts helped propel Silas's life, transform it, and then re-mold it for good. It is as if each theft is actually a blessing in disguise. Each theft took away different negative aspects of Silas's life, whether he knew it or not.
The first theft occurs in chapter 1, and it happens in Lantern Yard. Here, Silas is framed and falsely accused of stealing money from his own religious group. This was nothing but a terrible act of treason from his so-called friend, William Dane. The result of this false accusation was that Silas had to leave Lantern Yard, shamed and destitute, and start over at Raveloe.
This was, actually, a good thing. The way that William Dane's "narrow and slanted" gaze is described denotes someone who is not to be trusted. Yet, Silas was greatly submissive to his friend. Imagine what could have happened if he had lived an entire life at the mercy of a traitor? Moreover, Sarah (Silas's love interest) was obviously just as worthless of his trust. It took her no time to leave Silas behind in the midst of his turmoil and get together with none other than....William Dane!
Certainly, this event may have destroyed Silas's world, as he knew it, in Lantern Yard. However, it opened the door to a new experience. Unfortunately, Silas would not learn from it yet. Instead, he stubbornly decided to isolate himself, to dedicate himself to his job and to make as much money as he could. He used gold as a way to mitigate the sadness of the incident at Lantern Yard. Hence, it took another theft to bring Silas back into the reality of things again.
Silas Marner had lived in this solitude, his guineas rising in the iron pot, and his life narrowing and hardening itself more and more into a mere pulsation of desire and satisfaction that had no relation to any other being.
The second robbery was that of Silas's oh, so cherished gold. The shock of being robbed sends Silas into a shock that left him completely dependent on the very people whom he snubbed and isolated himself from.
These very people embraced Silas, kept him safe and warm, and watched out for his health. They took him in, regardless of his estranged behavior--which is exactly the opposite of what happened at Lantern Yard, where he was rejected and thrown away.
From the second theft also came the entrance of baby Eppie into the scene; she would eventually become Silas's most important person on earth, and his main reason to live. Even he admitted that Eppie's golden hair was the substitute for the gold stolen from him.
Again, had it not been for the robberies, what would have happened to Silas? Sometimes it takes chaos to bring back the order in our lives. Things do happen for a reason. Silas will come to learn this late, but at least not too late for him not to change for the better.