In plain words
The great soul from whom this principle of the Ātma comes so that it touches the heart is called the ‘guru’. The one in whose heart it takes root and whom it touches is called the ‘disciple’. The seed must be alive. The field must be ploughed and made ready for sowing. If both these come together, a true spiritual harvest comes forth in a most wonderful form. The listeners must have skill of Buddhi. Otherwise the knowledge of the principle is hard to take hold, hard to take root. Such are gurus and disciples. All the rest may be called ‘those who merely amuse themselves with spiritual ideas’.