Why will penance not lead to God, while knowledge will?

Penance is suffering of body by fasting, sitting nearby fire etc. The body and mind are interlinked and therefore, it leads to suffering of mind also. In the quest for the truth also, the mind suffers with anxiety. The latter type of suffering of mind is good because more the quest for the truth, more will be the absorption of the knowledge. In the former type of suffering, there is no quest for truth and hence, it will not help in the absorption of knowledge. However finally, knowledge alone shows the clear path of understanding to attain salvation. The quest for the truth can be considered to be devotion for knowledge and thus, devotion leads to knowledge. After receiving the true knowledge, you will clearly understand the goal and then devotion to the goal is developed. Thus, knowledge develops the devotion. However, the former devotion is devotion for knowledge and the latter devotion is the devotion for the goal. The devotion leads to practice and subsequent sacrifice. The fruit of sacrifice is salvation.