Sri Aurobindo states in his Synthesis of Yoga that a minimum of moral and psychological purification is necessary. We have to build the right climate for it before we start practising meditation in earnest.
With the right external conditions ready, we now enter the deeper phases of meditation. The fixed posture is taken, the breathing is regularised; the next step is pratyahara, bringing together.
If we are thinking, for instance, of God as Love, our whole consciousness gets suffused with the vibration of love; we sense God’s love permeating everywhere.