Sirach 19:19

19 The knowledge of the commandments of the Lord is the doctrine of life: and they that do things that please him shall receive the fruit of the tree of immortality.

Sirach 19:19 In-Context

17 Admonish thy neighbour before thou threaten him; and not being angry, give place to the law of the most High.
18 The fear of the Lord is the first step to be accepted and wisdom obtaineth his love.
19 The knowledge of the commandments of the Lord is the doctrine of life: and they that do things that please him shall receive the fruit of the tree of immortality.
20 The fear of the Lord is all wisdom; and in all wisdom is the performance of the law, and the knowledge of his omnipotency.
21 If a servant say to his master, I will not do as it pleaseth thee; though afterward he do it, he angereth him that nourisheth him.

The Brenton translation of the Septuagint is in the public domain.