The writer speaks of "steadfast love" and "faithfulness" as if they were people who could leave someone. The abstract nouns "love" and "faithfulness" can be stated as the verb "love" and the adjective "faithful." Also, the negative command can be stated positively. Alternate translation: "Love God without ceasing and be faithful to him" (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. Alternate translation: "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. Alternate translation: "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]])