“Dhyanam nirvishayam manah”: That state of the mind wherein there are no Vishayas or sensual thoughts is meditation.
“Tatra pratyayaikatanata dhyanam”: A continuous flow of perception or thought is Dhyana (meditation). There is continuous current in the mind of one object like the flow of water in a river (Pravaha). There is only one Vritti in the mind. It is Ekarupa-Vritti-Pravaha.
Meditation is the keeping up of an unceasing flow of God-consciousness. It is the flow of continuous thought of one thing or God or Atman, like the continuous flow of oil. All worldly thoughts are shut out from the mind. The mind is filled or saturated with Divine thoughts, Divine glory and Divine presence. Meditation is regular flow of thought with regard to the object of concentration. Meditation follows concentration.
Meditation is the seventh rung or step in the ladder of Yoga. Yogis call this ‘Dhyana.’ Jnanis term this ‘Nididhyasana.’ Bhaktas style this ‘Bhajana.’
Yama (self-restraint), Niyama (religious observance), Asana (posture), Pranayama (restraint of breath), Pratyahara (abstraction or withdrawal of the senses), Dharana (concentration), Dhyana (meditation), Samadhi (superconscious state or blissful union with the Supreme Self) are the eight steps of Yoga.
Lord Jesus says, “Empty thyself and I shall fill thee.” This corresponds to the teaching of Patanjali Maharshi: “Yogas-chitta-vritti-nirodhah”–”Yoga is restraint (annihilation) of all mental modifications (functions).” This emptying process or making the mind blank is no doubt a trying discipline. But continued practice of an intense type will bring success. There is no doubt of this.
— Swami Sivananda