The truth in Islam is simple. There is only one God, the Creator and Sustainer of the universe (blessed and exalted is He). We must not consider anyone or anything to be above or even equal to Him. The One True God (Allah) has created us to know and worship Him alone.
Islam answers this crucial question clearly and beautifully, and it reveals details about the unique nature and qualities of the One True God. The Glorious Qur’an states:
{Say: He is God (Allah) [Who is] One, God (Allah), the Eternal refuge; He neither begets nor is born, nor is there to Him any equivalent.} (112: 1-4)
The One True God (Allah) has created us to know and worship Him alone. Those who worship Him correctly, following His commandments completely, will be admitted to eternal life in Paradise.
Indeed, Islam recognizes our innate natures and answers our questions. It speaks to our souls and to our spiritual and intellectual needs and tendencies. Allah, Who knows the deepest secrets and thoughts in our souls, minds, and hearts, reveals to us the secrets that bring tranquillity and contentment to them. These are some keys and secrets to help us attain peace of mind:
Know your One True God.
Believe in Him alone.
Follow His Will and obey Him.
Believe in His prophets (including Prophet Muhammad).
Remember Him.
Seek His forgiveness.
Worship Him alone.
Wish for others what you wish for yourself.
Be generous to others and try to make them happy.
Be sincere and pious.
Muhammad is the final prophet in Islam, known as the 'Seal of the Prophets'. This means that Muslims regard Muhammad as Allah's final messenger.