The Holy Prophet [s] said that the disciples of Jesus [a] asked him with whom they should make friends, and he [a] replied: "With one whose presence reminds you of God, his speech increases your knowledge and his deed inspires you (to work righteously for) the next world."
Bihar-ul-Anwar, vol. 1, p. 203
Amir ul Mu'mineen Ali [a] said: "No business should hinder you from being busy doing good for the coming world, hence, surely, the length of opportunity is a very short time."
Ghurar-ul-Hikam, p. 335
Amir ul Mu'mineen Ali [a] said: "He who sells his next life for his present life in this world, loses both of them."
Ghurar-ul-Hikam, p. 274
Imam Hadi, the tenth Imam, [a] said: "Remember when you are on your deathbed and your body is lying before your family members, then there is no physician to prevent you (from death) nor a friend to avail you."
Bihar-ul-Anwar, vol. 78, p. 370