כוונות
In the classical sources, then, kavvanah means chiefly concentration on the meaning of the words of the prayers and the realisation that one is in God's presence. In the Kabbalah, however, and especially in the Lurianic version, the whole doctrine of kavvanah receives a totally different meaning. Mystical contemplation is now the order of the day. The Kabbalist is expected to have in mind, when he prays, all the complicated combinations in the Sefirotic realm. Each word of the prayers has not only its surface meaning but represents one of the divine names in combination. By having these in mind the Kabbalist actually promotes harmony among the Sefirot. He sends upwards, as it were, the power of the divine names, he repeats the creative processes on high, and by so doing he assists the flow of divine grace through all creation. Of these thoughts that the Kabbalist is expected to have in mind, the plural kavvanot is used. Prayer involves for the Kabbalist both a profound knowledge of the whole Kabbalistic scheme and its application in severe contemplation during his prayers. Instead of kavvanah in the older non-mystical sense, the key-word is now kavvanot. The Lurianic Prayer Book was compiled in order to place before the mystical adept the 'correct' words and order of the prayer, i.e. those representing the divine mysteries which he follows in the ascent of his soul. The Hasidim substituted the Lurianic Prayer Book for the older Ashkenazi Prayer Book precisely because of the doctrine of the kavvanot, though whether the Hasidim actually practised the technique of kavvanot is another
question... Even if the early Hasidim did not actually practise the kavvanot there is no difficulty in the fact that they adopted the Lurianic Prayer Book because, as is frequently
stated, they believed that, even without the worshipper having them in mind, the kavvanot were still, as it were, sent on high to have their effect.
What is certain is that in the school of the Maggid of Meseritch, the disciple of the Baal Shem Tov, the practice of the Lurianic kavvanot gave way to the use of prayer as a means of 'awakening love and fear' in which the technique of 'attachment to the letters' was used. In this school the practice of the kavvanot was a positive hindrance to the ideal of devekut.
How could the worshipper become attached to God and have only God in mind if, at the same time, he was expected to engage in the very severe intellectual effort of retracing the details of the Sefirotic map? A new technique of contemplation was required and this was 'attachment to the letters'.
Louis Jacobs, Hasidic Prayer pp. 73-75.