Those who have reached the highest perfectional stage of mystic power and can see everything in the past, present and future are called tri-kala-jnas. Similarly, the devotees of the Lord can see everything clearly that is in the revealed scriptures. The devotees of Lord Sri Krsna can very easily understand the science of Krsna, as well as the situation of the material and spiritual creations, without difficulty. Devotees do not have to endeavor for any yoga-siddhi, or perfection in mystic powers. They are competent to understand everything by the grace of the Lord, who is sitting in everyones heart.