To your Guru ever say yes.
Obedience to him leads to success.

Guru Nanak Dev founded a new village and named it Kartarpur. The Guru used to do farming there. He met daily with the people in the village to tell them about God and the goal of human life. Bhai Lehna, a resident of village Khadur, believed in the worship of the goddess Vaishnav Devi. Once during his annual trip to that goddess, he wanted to meet the Guru as well. Bhai Lehna reached Kartarpur, heard the Guru's preaching, and finally received the peace for which he had so long been searching. Bhai Lehna, therefore, gave up his regular pilgrimage to the goddess and decided to settle at Kartarpur to enjoy and follow the preaching of the Guru to realize the goal of his life.

During his stay at Kartarpur, Bhai Lehna remained in the service of the Guru. He did everything the Guru wished him to do. In this way he became one of the very close followers of the Guru.

There are many sakhis about the obedience of Bhai Lehna, telling us how he gave up his ego and followed the path shown by the Guru. He was never reluctant to do what the Guru wanted the Sikhs, or Disciples, to do. Two sakhis given below tell us about the sincere love and commitment of Bhai Lehna for the Guru.

1) One day while working in the rice fields, some grass growing in the crop was removed. It was to be fed to the animals in the house. The Guru asked his sons, Bhai Sri Chand and Bhai Lakhmi Chand, to carry the bundle home. They declined to do so because the muddy water dripping from the wet roots of the grass would spoil their clothes. When the Guru looked towards Bhai Lehna, he immediately picked up the bundle of grass and brought it home. This act of devotion by Bhai Lehna pleased the Guru very much.

2) Once Guru Nanak Dev was taking a bath and while doing so, the cup he used for pouring water slipped and rolled into a pit containing dirty water. When asked to take out the cup, the sons of the Guru advised him to get that dirty job done by someone else. Bhai Lehna, however, did not mind at all. He put his hand in the dirty water, took out the cup, cleaned it and handed it over to the Guru.

The thorough destruction of his ego and his complete obedience to the Guru made Bhai Lehna suitable to be chosen as the second Nanak. Before his death, Guru Nanak Dev passed on the responsibility of the Guruship to Bhai Lehna and named him Angad Dev.

Discipline is key to spiritual attainment.