en_tn/mrk/06/51.md

They were completely amazed

If you need to be more specific, it can stated what they were amazed by. AT: "They were completely amazed at what he had done" (See: rc://en/ta/man/translate/figs-explicit)

what the loaves meant

The phrase "the loaves" refers to when Jesus had multiplied the loaves of bread. This can be stated more clearly. AT: "what it meant when he had multiplied the loaves of bread" (See: rc://en/ta/man/translate/figs-ellipsis)

their hearts were hardened

Having a heart heart represents being too stubborn to understand. AT: "they were too stubborn to understand" (See: rc://en/ta/man/translate/figs-metaphor)