This particle means mitigation requirements. Принеси-ка, подай-ка, налей-ка.

It is used for softening commands or requests, informal way to express it. It can be used not only with this verb: встань-ка, подумай-ка, подай-ка. Only informal. It's formed with imperative verb+ка.

I would like to add that verb with the "ka"-ending very similar with constructions "Ну-ка +verb" and "a ну +verb", but the last one just a little ruder. (I thought, if you already know this words and constructions it will be easier for you to understand) For example, "Принеси-ка воды"= "А ну, принеси воды", "Иди-ка умойся"="А ну, иди умойся", "Посмотри-ка в окно"="Ну-ка, посмотри в окно", "Повиси-ка на нем"="Ну-ка, повиси на нем" This is sort of call to action.

Every language has ways of expressing nuances and emotional tendencies. They all have explanations. The fact that such a expression or particle does not exist in another language does not mean it cannot be explained. I prefer to have the explanation rather than guessing what it could mean... which could subject me to mistakes. The three persons that answered gave good answered even though it was not so clear in the beginning, with the examples it was easier to understand.

IvanSaxonov, а если перед этим предложением добавить "Видишь, там, на горе, возвышается крест", смысл появится? )