It is impossible to pray with kavanah (devotion) without exertion. 1 You must entreat God for help and assistance. 2

Consider that it is to your benefit when God helps you to have complete kavanah for half or most of your prayer. If, in the end, you feel weak and the deveikut is lost, what can you do? Pray to the best of your ability with lesser kavanah until the end of Aleinu [i.e., the concluding prayer]. 3