We are told, "Know this day and take it to your heart...."[i] But if we know something, why is that not enough? What does taking it to heart add? Knowing something means that you understand that thing, at least you certainly have that information somewhere in your head. But taking it to your heart means that you live with that awareness in your daily life.
The main reason Torah observance has become a burden to so many religious Jews is that even though these very fine Jews know that Hashem exists, and they know that He is everywhere, but still, they have not yet taken this information to heart.
Since we all know that Hashem fills and surrounds us, (He is Infinite and the Infinite has to be everywhere), and we surely know that He told us to fulfil His mitzvahs, but still if you have not taken His reality to heart, if you do not live knowing that Hashem is actually right here inside our very breath filling and surrounding us, then you might very well come to observe the Torah in a cold, distant way... as an obligation at best. But when we go through our day aware of Hashem's reality…, His very closeness, then we do the mitzvahs with freshness, with love and joy.
This information is all you need to live a joyful Torah observant life, but only on one condition... that you take it to heart … that you make it your ongoing experience, that you remember that Hashem is right there with you all day long.
And then, when you have taken it to your heart … then you will be able to share it with your children so they too will live joyful, Torah lives.
[i] Deuteronomy 4:39