R’ Shmuel HaLevi Wosner zt”l (Shevet Halevi) would say: “"ולמדתם אתם את בניכם לדבר בם" - Why do we say 'את בניכם' instead of the simpler and shorter 'לבניכם'? The Torah speaks to the mitzvah of Chinuch three times: in Parshas Vaeschanan twice (VeShinantam, VeHodatam) and here in Parshas Eikev. Each time contains a deeper meaning: The mitzvah of ‘Veshinantam’ speaks to making the words of Torah strong and clear, the mitzvah of VeHodata speaks to the responsibility of how the Torah was acquired experientially. Here, though, while the posuk does speak to acquiring a Derech, it requires a back and forth face to face meeting, thus it says,'את בניכם'.”
A Wise Man would say:
“Friendship is very much like money, it is easier made than kept.”