Q 7: How could Allah's slaves know what He loves?
A--- They know it through the coming of Messengers and the Revelation of the Heavenly Scriptures that contain the ordainments and prohibitions of Allah the Almighty. Thus; He presented His irrefutable proof and showed His infinite wisdom to all mankind.
Allah the Almighty says:
{Messengers as bearers of good news as well as of warning in order that mankind should have no plea against Allah after the (coming of) Messengers}. (An-Nisa', 165)
He says: {Say (O Muhammad (Peace be upon him) to mankind):
If you (really) love Allah then follow me,2 Allah will love you and forgive you your sins. And Allah is Oft-Forgiving, Most Merciful}.
Reference: 200 FAQ On Muslims Belief - Shiekh Hafiz Ibn Ahmed Al Hakami