Do you want to be pure? Then concentrate all day on God’s name. Do japa [repetition of one of God's names or the name of your deity or your mantra] and think of His glories. What you think you become. How great must be japa.
Concentration is a supreme discipline. Is meditation so easy? The great Rishis [Seer-saints] struggled. Sri Ramakrishna himself struggled for twelve years.
Intense yearning can come any time, in any of the four ashramas*. Intensify a little the desire you have for God. The highest happiness is to know God, live with God, become God, and to know that God is there. His touch is so electrifying, it destroys all past karmas [negative conequences]. God’s embrace is not like yours and mine.
Do not waste your time. Read the scriptures and think. You and the scriptures must be the closest companions because the scriptures give the milk of Immortality.
Cling to the inside, not the outside. He is seated in your heart. Do not hurt anyone in thought, word or deed. That is the essence.
*The four ashramas or stages of life are brahmacharya (the student life), grihasta (married life) vanaprastha (wandering/contemplating in forest phase - not necessarily literally of course) and sannyasa - where one has renounced the world and one's attachments.