There are two blessed parties that tread the path of God. Firstly, those who adhere firmly to the fundamental principles of religion without any real insight (din-ul-aja’iz), or in other words, those who follow the shariah and thus attain salvation. Then, there are those who advance even further still. Whatever the odds, they do not tire and continue to march forward until they reach their ultimate objective. However, truly unsuccessful are those who advanced forward from the rank of din-ul-aja’iz but did not complete their spiritual quest; such people always fall prey to atheism. In this context, some people assert that they have observed their Prayers and undertaken periods of reclusion for spiritual exercise, but to no avail. For example, a man named Mansur Masih states that the reason he become a Christian was due to the fact that he turned to various spiritual preceptors and went into 40-day retreats but none of this bore any fruit; so he became averse to Islam and accepted Christianity.
(Hazrat Mirza Ghulam Ahmadas, Malfuzat, Vol. 1, pp.22-23)