Both New Revised Standard Version and Good News Translation begin a new paragraph here because the subject changes to instruction about wages and other matters.

Do not keep over until the next day the wages of those who work for you: It was laid down in the Law of Moses that payment should be given on the same day that services are rendered (compare Lev 19.13; Deut 24.14-15).

If you serve God you will receive payment: If you serve God refers to serving God by obeying the command to pay workers every day. Good News Translation makes this clear by saying “Honor God in this way.”

Watch yourself, my son … discipline yourself …: These two final clauses are almost the same in meaning. Good News Translation combines them with “Behave properly at all times,” and Contemporary English Version has “Have self-control in everything you do.” Another way to say this is “Walk your life in a self-controlled way at all times.”

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on Tobit. (UBS Helps for Translators). New York: UBS, 2001. For this and other handbooks for translators see here.