The writer speaks of his words preserving a person's life as if they were that person's life. AT: "my words give life" or "the things I say give life" (See: [[rc://en/ta/man/translate/figs-metonymy]])
The writer speaks of fully understanding his words as if the person searches for them and finds them. AT: "to those who understand and practice them" (See: [[rc://en/ta/man/translate/figs-metaphor]])
The word "their" refers to "those who find them." The subject for this phrase can be supplied from the previous phrase. AT: "my words will give health to the whole body of those who find them" (See: [[rc://en/ta/man/translate/figs-ellipsis]])
Here the word "heart" represents a person's mind and thoughts. AT: "Keep your mind safe and guard your thoughts" (See: [[rc://en/ta/man/translate/figs-metonymy]])
# with all diligence
with constant and earnest effort
# from it flow the springs of life
The word "it" refers to the heart, which is a metonym for the mind and thoughts. The writer speaks of a person's life as if it were a flowing spring that originates from the heart. AT: "from your thoughts comes everything you say and do" or "your thoughts determine your course of life" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-metaphor]])