‘Does the Lord delight in burnt offerings and sacrifices
    as much as in obeying the Lord?
To obey is better than sacrifice,
    and to heed is better than the fat of rams.
For rebellion is like the sin of divination,
    and arrogance like the evil of idolatry.
Because you have rejected the word of the Lord,
    he has rejected you as king.’ (1 Samuel 15:22-23)

The Hebrew word that is translated ‘to obey’ is שָׁמַע ‘to hear’.  When God speaks, all must not simply hear, but listen and take heed.   The same imperative proceeds what Jesus defines as the Greatest Commandment:

Hear, O Israel: The Lord our God, the Lord is one.You shall love the Lord your God with all your heart and with all your soul and with all your might.  (Deuteronomy 6:4)