Om Swami
Why is telling the truth called the greatest spiritual practice?
Truth is the greatest sadhana
Speaking truth is the greatest sadhana (spiritual practice) and the greatest penance. The vow of not telling a lie is the basis of all tapas (austerity).
Telling the truth is the greatest sadhana. This has been said before: there is no penance equal to truth and no sin equal to lying. It is the greatest penance there is.