Knowledge is the first face of Truth. It is information, facts, academic and utilitarian. It is a beginning, but only the beginning.
Wisdom is the second face of Truth. It is Knowledge applied to life. It is theoretical but useful. It is necessary if one is to actually benefit from Knowledge.
Gnosis is the third face of Truth. It is Wisdom experienced. Having applied Knowledge to life, and having experienced the Truth of that Wisdom, we achieve the understanding of Gnosis, Truth through Experience.
Acquire Knowledge, for it is valuable. Learn Wisdom for it too is valuable. But to achieve Gnosis is to understand the Mystery of Truth. This is the purpose of Life.