Is the worship of God necessary?

God does not insist that we worship him. In His generosity, He gives to all, the high and the low, the educated and the illiterate, even to those who are anti-God – Atheist.
Some people are under the impression that God, just like an army commander, demands respect and worship. God does not need man’s flattery or praise. Guru Nanak Sahib Ji says:

ਜੇ ਸਭਿ ਮਿਲਿ ਕੈ ਆਖਣ ਪਾਹਿ ॥ ਵਡਾ ਨ ਹੋਵੈ ਘਾਟਿ ਨ ਜਾਇ ॥੨॥
“If all people start praising Him, it will not make the least difference to His greatness.”
(Ang 9)

Just as the sun does not need light of the lamps so in the same way, God does not need the praises of men.
God is not a Dictator. People worship Him from a sense of duty, Dharma. They are convinced that God who made this universe can be known and loved. Those who know His nature and qualities are wonder-struck by His greatness. In their ecstasy, they exclaim “Waheguru” , Wonderful Lord. They want to love Him as devotedly as a wife loves her husband.
Moreover, many people feel that human life is the supreme opportunity for spiritual attainment. A worldly man who makes no effort towards spirituality stands in great danger of joining the cycles of birth and death.
A sense of spirituality is a sheet-anchor for the individual. It gives purpose and meaning to life. Guru Arjan Ji writes in Sukhmani Sahib:

ਪ੍ਰਭ ਕੀ ਜੋਤਿ ਸਗਲ ਘਟ ਸੋਹੈ ॥
“The Light of God is in all hearts.”
(Ang 282)

Thus, a sense of emptiness may be replaced by a sense of richness. Only those who are egoistic and wallow in their material possessions, refuse to accept the comfort of divinity.
Man is not potentially evil, but is weak and ignorant. When temptation faces him, he is likely to succumb to it. At that moment, he needs a support, an inspiration. If he remembers his divine essence and calls on his moral courage, he will get the necessary strength to overcome the temptation.
A positive approach to God will yield results. Union with God is our goal. His great qualities, Truth, Goodness, Beauty, Love, Purity, Peace, Wisdom, Justice, Mercy etc. are the ladder to Him. By concentrating on these qualities, we through auto suggestion, imbibe such qualities. Man rises to God, while God stoops to lift man.