In the first chapter of the Mesillas Yesharim, the Ramchal writes:
“We thus derive that the essence of a man’s existence in this world is solely the fulfilling of mitzvos, the serving of God and the withstanding of trials, and that the world’s pleasures should serve only the purpose of aiding and assisting him, by way of providing him with the contentment and peace of mind requisite for the freeing of his heart for the service which devolves upon him.”
The Chofetz Chaim in the beginning of his Biyur Halacha commentary on the first Halacha in the Shulchan Aruch writes:
“I Place Hashem Before Me Always – Is A Crucial Principle Of The Torah.” The person who wants to fulfill “I place Hashem…” properly, must make himself zealous to fulfill what is written in the name of Sefer HaChinuch. And because this is so greatly precious, many Torah authorities copied this in their books. The Chinuch mentioned this in the introduction and in several sections. This refers to six mitzvos that are obligatory continuously. These will never stop or part from a person, even for a single moment, all of his days. At every time and moment that a person thinks into these, he fulfills active commandments, and there is no limit to the amount of reward given for the mitzvos. ”
The Chofetz Chaim gives a short commentary on these six mitzvos and here is an excerpt specifying the mitzvos and the Pasukim from which they are derived:
1. To believe that there is one G-d in existence Who made to exist everything which exists…And this is an active commandment, as the Torah says, “I am the L-rd your G-d Who took you out of the land of Egypt, from the house of slavery.”
2. We are to never believe in any other god beside Him, as the Torah says, “You will not have any other gods besides Me.”
3. To attribute oneness to Him, as the Torah says, “Hear, Israel, the L-rd is G-d, the L-rd is one.”
4. To love the Omnipresent, may He be blessed, as the Torah writes, “And you will love the L-rd your G-d with all your heart…”.
5. To have fear of Hashem, may He be blessed, before oneself in order to remain free of sin. On this the Torah says, “Fear the L-rd your G-d.”
6. Not to stray after the impulses of the heart. The substantiation for this is the Torah verse, “And do not go straying after your hearts and after your eyes.”
(For a full translation of the Chofetz Chaim’s commentary on the six constant mitzvos, please see Rabbi Jeff Forsythe’s translation here.)
Hashem in his kindness gave us Six Constant Mitzvos, six constant opportunities to connect to Him and take a step towards fulfilling our purpose in life. It just takes a quick thought when we’re sitting, standing, walking, driving or about to perform a mitzvah. As the Chofetz Chaim says “there is no limit to the amount of reward”.