Creation of Shabad Hazaray
A cousin of Guru Ram Das came to Amritsar from Lahore especially to ask Guru Sahib to attend his son's wedding. Guru Ji said, "I will not be able to go because I can't leave my duties here as Guru. Perhaps I can send one of my sons instead."
Guru Ram Das Ji had three sons: Baba Prithi Chand or Prithia, Baba Mahadev and Arjan Mal. Prithia was in charge of collecting donations, of which he secretly took a portion for himself. When the Guru asked him to attend the wedding, Prithia said, "I have to take care of the collections. And I hate going to weddings."
Actually, he was afraid if he were away from the Guru for too long, he might not be appointed the Guru's successor. Having no luck with Prithia, Guru Ji then turned to Mahadev. Mahadev lived his life in meditation and said, "I have no desire to involve myself in worldly affairs."
Finally, Guru Sahib Ji asked Arjan if he would go. Arjan said, "I only desire to do what you wish." Guru Ji was very pleased. He asked Arjan to spend some time in Lahore to share the Guru's teachings with the Sikhs there. Any donations he received were to be given to the free kitchen to feed the poor. The last words he said to Arjan were, "You should stay in Lahore until I send for you by letter."
In Lahore with sangat
Arjan Mal stayed in Lahore after the wedding and grew to be much loved by his relations and the Sikhs there. Still, all the time he was there, his heart was with his father, Guru Ram Das Ji. When he expressed his longing to his new friends, they suggested he write a letter asking that he be able to return. Arjan Mal wrote a beautiful shabad :
"My soul longs for the Guru like the pied-cuckoo longs for the rain of the monsoon. I am always a sacrifice unto the True Guru."
He sent this letter with one of the Sikhs who had come with him to Lahore. When the messenger reached Amritsar, Prithia saw him and suspected that he had a letter for the Guru from his brother. He said,"I will take the letter to the Guru myself." When he read the letter he knew that it was so beautiful that it would move the Guru's heart in Arjan's favor. So he hid the letter in his coat and sent the Sikh back to Arjan telling him that the Guru said he should stay in Lahore until sent for. When Arjan received this message, he knew that Prithia, and not his father, had sent the message.
Second letter also intercepted
He then wrote a second letter with strict orders that it be given only to the Guru. In it, he wrote, "I love the sight of the Guru's face and the sound of his words, and it has been long since I have seen him. I am ever a sacrifice unto the True Guru." This time, Prithia grabbed the letter out of the messenger's hands, and grew more angry than before. Again, he hid the letter in his coat. He sent another message that Arjan was to remain in Lahore until sent for. When Arjan heard this from the messenger, he wrote a third letter, this time putting a number "3" on it. He told the messenger to be on his guard against Prithia and to give the letter to Guru Ram Das Ji himself. The messenger waited until Prithia had to go home, and then quickly reached the Guru and gave him the letter.
In it, Arjan said, "Each second away from the Guru is like an age. I cannot sleep without a sight of the Guru. I am ever a sacrifice unto him." On this letter, the Guru saw the number "3", and knew instantly that he had not received the other two letters. The messenger related the story to him, and the Guru grew very angry. He called for Prithia and asked him three times if he knew anything about the other letters. Prithia denied it everytime. The all knowing Guru knew his thoughts, and told the messenger to go get the coat in Prithia's house. When he returned with it, the two missing letters were in the pocket. The Guru charged Prithia with lying in front of the whole congregation, and laid bare his disobedience to the Guru.
Guru Ram Das sends for Arjan
At once, the Guru sent Bhai Buddha to Lahore with a carriage to bring Arjan Mal home as soon as possible. When Arjan was finally united with his father, he placed his head on Guru Sahib Ji's chest against his long beard. He remained that way for many moments, while the Guru held him gently in his arms. The Guru then said that as he had written three stanzas, he should write a fourth to finish the poem. Arjan wrote the last verse saying, "It is my good fortune to have met the True Guru, and I have found the Immortal God in my own home. My greatest desire is to never be separated from him again, not even for an instant. I am ever a sacrifice to the True Guru."
Upon hearing this, the Guru was very pleased. He said, "The Guruship is passed on because of merit. As only the one who is most humble can claim it, I grant it to you." Guru Ji then sent for a coconut and five paisey and placed them before Arjan. He descended from his throne and seated Arjan upon it in front of the whole sangat. Bhai Buddha pressed the tilak on Arjan's forehead as a symbol that the light of Guru Ram Das Ji had now passed to Arjan, who then became Guru Arjun Dev Ji the fifth Guru of the Sikhs.
The poem that Arjan wrote is called Shabd Hazare. It is so beautiful that it is worth the singing of a thousand shabds.
Above based on text from www.info-sikh.com