Deuteronomy 8:1

All the commandments which I command thee this day shall ye
observe to do
It is repeated over and over again, to impress it on their minds, and to show the importance and necessity of it, how greatly it was expected from them, and how much it was incumbent on them:

that ye may live and multiply, and go in and possess the land which the
Lord sware unto your fathers;
for their temporal life, and the mercies and comforts of it, the multiplication of their offspring, and of their substance, their entrance into the land of Canaan, possession of it, and continuance in it, all depended on their obedience to the commands of God; see ( Deuteronomy 19:20 ) .