The writer speaks of "covenant faithfulness" and "trustworthiness" as if they were people who could leave someone. The abstract nouns "faithfulness" and "trustworthiness" can be stated as "faithful" and "trustworthy." And, the negative command can be stated positively. AT: "Always be trustworthy and be faithful to the covenant" (See: [[rc://en/ta/man/translate/figs-personification]] and [[rc://en/ta/man/translate/figs-abstractnouns]])
The writer speaks of faithfulness and trustworthiness as if they were objects that a person could tie around the neck like a necklace. The image suggests that these are valuable things that the person displays outwardly. AT: "display them proudly like one would wear a necklace" (See: [[rc://en/ta/man/translate/figs-metaphor]])
Here the heart represents a person's mind. The mind is spoken of as if it were a tablet upon which someone can write messages and commands. AT: "always remember them, as if you had written them permanently on a tablet" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-metaphor]])