Partial Obedience is still Disobedience. God wants us to be fully committed to Him and if we don’t follow His words exactly then there is the smallest sliver of doubt, of a lack of faith in Him.
Take Abraham for example, God called him to sacrifice his only son. That was all of Abraham’s bloodline, it was his heir that would continue on the family. But God called him to sacrifice him. Abraham did it, he probably didn’t like the thought of killing his only son, but he didn’t question God. Abraham let his faith in God guide him and God stopped him saying that his faith was proven and God said to Abraham “… I will surely bless you and make your descendants as numerous as the stars in the sky and as the sand on the seashore…”
Because of Abraham’s complete obedience God rewarded him. We must be like Abraham, don’t doubt God, let our faith lead us, and obey.