Here's why:
* Traditional grammar: Traditional grammar rules sometimes discourage starting sentences with prepositions (like "for," "on," "in," etc.) because it was seen as less elegant.
* Flow and emphasis: Starting a sentence with "for" can make the sentence feel a bit clunky, as it often sets up a reason or purpose before stating the actual action. It can also make the sentence sound less direct and emphatic.
Examples:
* Less formal: "For I have a plan, my friend."
* More formal: "I have a plan, my friend."
However, there are times when starting with "for" can be perfectly fine and even preferred:
* Emphasis: You can use "for" to put emphasis on the reason or purpose: "For your sake, I will do it."
* Connecting ideas: "For" can be used to connect a sentence to a previous idea: "The weather was bad. For this reason, we decided to stay home."
* Informal speech: In casual conversation, it's perfectly acceptable to start sentences with "for."
In short:
While there's no strict rule against starting a sentence with "for," it's often more elegant to use other sentence structures. But feel free to break the rule if it helps you achieve the right tone and emphasis for your writing.