Bhagavad Gita 6.43तत्र तं बुद्धिसंयोगं लभते पौर्वदेहिकम्।यतते च ततो भूयः संसिद्धौ कुरुनन्दन ॥

When he takes a human body again in this world his previous exertions and practice in the path of Yoga are not wasted. They bear full fruit now, and hasten his moral and spiritual evolution.Our thoughts and actions are left in our subconscious minds in the form of subtle Samskaras or impressions. Our experiences in the shape of Samskaras, habits and tendencies are also stored up in our subconscious mind. These Samskaras of the past birth are revivified and reenergised in the next birth. The Samskaras of Yogic practices and meditation and the Yogic tendencies will compel the spiritual aspirant to strive with greater vigour than that with which he attempted in the former birth. He will endeavour more strenuously to get more spiritual experiences and to attain to higher planes of realisation than those acired in his previous birth.