Deuteronomy 4:9

Only take heed to thyself
To walk according to this law, and not swerve from it:

and keep thy soul diligently;
from the transgressions and breaches of it:

lest thou forget the things which thine eyes have seen;
either the statutes and judgments set before them, and the circumstances of the delivery of them; or the punishment inflicted on the breakers of them; or the favours bestowed on those that observed them:

and lest they depart from thy heart all the days of thy life;
out of thy mind and memory, and have no place in thy affections, through a neglect and disuse of them:

but teach them thy sons, and thy sons' sons;
their children and grandchildren, that they may be trained up in them in their youth, and so not depart from them when grown up, and in years; see ( Deuteronomy 6:7 ) .