What is meant by worship?
Worship is a collective name for everything Allah the Almighty loves and satisfied with, being words or deeds,apparent or hidden and keeping away from anything that is contrary to that.

When is an action considered to be worship?
An action is considered as worship when two conditions are fulfilled,they are:perfect love and complete humility for Allah(swt).Allah the Almighty says in the glorious Quran in Surah Al-Baqarah 2:165-But those who believe are stronger in love for Allah" .In another verse of Surah Al-Muminoon 23:57,He says-"Indeed,they who are apprehensive from fear of their Lord" .
Allah (Exalted He) has combined between love and humility in the glorious verse of Surah Al-Anbiyaa 21:90-"Indeed,they used to hasten to good deeds and supplicate Us in hope and fear and they were to Us humbly submissive".


Sign of the servant's love for his Lord
The sign is that he loves what his Lord Allah loves and hates what He hates.Also,he obeys His laws and orders and stays away from His prohibitions.In addition,he is loyal to the righteous doers and saints (the believers) and not be friendly to the disbelievers.It is for this reason that to love someone for the sake of Allah and to hate for the sake of Allah is counted to be the strongest bond of Imaan,i.e. a believer loves and shows loyalty to a person who is obedient to Allah the Almighty and in contrary he refrains from being a friend of the one who commits sins and doesn't believe in Allah the Lord of the worlds.

How do people know what Allah loves and satisfied with?
People know what Allah the Almighty loves through the Messengers who were sent to them and the books that have been revealed.It was by means of those Messengers and books the Lord commanded what He loves and forbade what He dislikes and rejectes.Based on this, irrefutable evidences have been established against them and His great wisdom has manifested.Allah (Exalted He) says in Surah An-Nisa 4:165-"[We sent] messengers as bringers of good tidings and warners so that mankind will have no argument against Allah after the messengers".
He also says in Surah Al-Imran 3:31-''{Say, [O Muhammad],"If you should love Allah, then follow me,[so] Allah will love you and forgive you your sins.And Allah is Forgiving and Merciful"}.