ON SELF PURIFICATION
"Certainty is complete belief."
God, the Supreme, in His supreme justice, has associated happiness and comfort with certainty and contentment [that is, resignation to God's will], and coupled sorrow and pain with doubt and resentment [with respect to Divine will] ~ Imam Ja'far al-Sadiq
Imam al-Rida (A) has been quoted as saying: Worship does not lie in copious prayer and fasting, but in the amount of contemplation in the works of God. ['Laisat al-`ibadah kathirat as-siyami was-salati innama al-ibadah kathirat-tafakkur fi `amrillah.}
Here it is important to point out that invocations and supplication prescribed in the religious law, although are worships and could be a means of achieving God's nearness but, their main aim is attaining the stage of absolute cut off from other than God, and absolute attention and heart's presence towards God-Almighty. Therefore, simply recital of phrases without paying attention towards their meanings and remaining negligent towards the real aims behind them would not produce any result. Because, recital of invocations and even their continuous repetition is not so difficult but this action alone may not help a wayfarer attaining his cherished goal.
What is useful is concentration and heart's presence towards God-Almighty, and negation and complete cut off from every thing other than Him, which is extremely difficult. So far as one does not achieve negation of others than God, he does not attain the worthiness and decency of receiving God's blessings and illuminations. Only a heart absolutely and thoroughly cleansed from all existence other than God -has the honor of becoming a sacred place for the illumination of Divine light. Attaining concentration of thoughts and negation of things other than God requires serious decision, perseverance, supervision, and constancy. It is not so that one will achieve it during the first attempt without practice and undertaking exercises. We must treat the self cautiously and should make him habitual of this act gradually. ~ http://www.al-islam.org/selfbuilding/19.htm#r1