Here "holds it tightly" is an idiom that means to continue to observe something. Alternate translation: "who is careful to always do this" (See: [[rc://en/ta/man/translate/figs-idiom]])
Here the "hand" represents the whole person and emphasizes the person's actions or behaviors. Alternate translation: "does not do evil things" (See: [[rc://en/ta/man/translate/figs-synecdoche]])