I often hear this as writers talk about having a great beginning. Why? To hook your reader, editor or agent. Great beginnings aren't only about the first sentence, it can be the first few paragraphs or page.
For now I'll say something about a few sentences. Having a great beginning is essential. My very first novel published by the Wild Rose Press began liked this.
Divorce, what divorce? Michele Ranieri cursed under his breath. He shook his head. How can there be a divorce when they didn’t consummate the marriage?
I had to look that up as I had no idea at what I had written. Those very sentences made me question? Why didn't they consummate the marriage? Something must have been terribly wrong if that was the case. What happened?
Are you absolutely insane? Please tell me you haven't signed the contract? (Rachael Johns, Man Drought)
Wow that first sentence hooked me, what about you? It forced me to ask questions.
The gun coughed in the still humid night. Without even a breath of a cry the young man dropped where he stood, his blood a darkening stain seeping into stark white sand, that shimmered in the silver moonlight. (Helene Young, Wings of Fear)
Study the first pages of novels you loved. See how the first line, the first few paragraphs hook the reader, and then apply a hook to your own work.
Before I go, here is the first line of my current wip (work in progress)
Of all the places in the world, he didn't want to be here.
I think I'm off to a good start. I said a start. lol. :) (added note) Well, this sentence has now changed at least 10 times, and probably a few more until I'm satisfied I have the best beginning for this novel I can possibly have.
Have a great week. I'll be trying to fit as much writing time as possible in this week, so have a great week. :)