(ד) שְׁמַ֖ע יִשְׂרָאֵ֑ל יְהוָ֥ה אֱלֹהֵ֖ינוּ יְהוָ֥ה ׀ אֶחָֽד׃ (ה) וְאָ֣הַבְתָּ֔ אֵ֖ת יְהוָ֣ה אֱלֹהֶ֑יךָ בְּכָל־לְבָבְךָ֥ וּבְכָל־נַפְשְׁךָ֖ וּבְכָל־מְאֹדֶֽךָ׃ (ו) וְהָי֞וּ הַדְּבָרִ֣ים הָאֵ֗לֶּה אֲשֶׁ֨ר אָנֹכִ֧י מְצַוְּךָ֛ הַיּ֖וֹם עַל־לְבָבֶֽךָ׃ (ז) וְשִׁנַּנְתָּ֣ם לְבָנֶ֔יךָ וְדִבַּרְתָּ֖ בָּ֑ם בְּשִׁבְתְּךָ֤ בְּבֵיתֶ֙ךָ֙ וּבְלֶכְתְּךָ֣ בַדֶּ֔רֶךְ וּֽבְשָׁכְבְּךָ֖ וּבְקוּמֶֽךָ׃ (ח) וּקְשַׁרְתָּ֥ם לְא֖וֹת עַל־יָדֶ֑ךָ וְהָי֥וּ לְטֹטָפֹ֖ת בֵּ֥ין עֵינֶֽיךָ׃ (ט) וּכְתַבְתָּ֛ם עַל־מְזוּזֹ֥ת בֵּיתֶ֖ךָ וּבִשְׁעָרֶֽיךָ׃
4: Hear Israel, Hashem our G-d Hashem is one. 5: You should love Hashem your G-D with all your heart, all your soul, and all of your money. 6: And these are things that I am commanding you today on your hearts, 7: that you will teach your children, speak about when you are home or when you are walking outside, and when you go to sleep and wake up. 8: And you will tie these words on your hands and put between your eyes. 9: And you will put these words on the doorposts of your house and your gates.
If we don’t teach our children sharply, it will sound like we don’t really understand or know the Torah. Normally when people don’t know things it is a sign that it isn’t important to them. Then it will be showing our children that the Torah isn’t important, therefore we have to teach our children sharply.
(Rashi ו:ה וּבְכָל־נַפְשְׁךָ֖)
וּבְכָל־נַפְשְׁךָ֖- We should love Hashem so much that we are serve him with all our soul. To serve him with all our soul, we have to love him even when we die, and he takes our soul.
If we think of the Torah as brand new, it then compares to anything else new that everybody wants to get and is interested in. Although if we look at it as something old, it then compares to everything that's old, boring and already forgotten. Therefore we must look at the Torah as if it is something new, because we should always be interested in it, and we should never forget it.
Just like a Doctor knows many names for different parts of your body, we as Jews, should know a lot about Hashem, Israel, and the Torah.
Another way to think of this is: You can call a basketball team, a really good team, but in the team there are individual players. Clearly the players are good based on the first statement but in order for them to be good they would each have to understand the game and be devoted on their own.