Our most spiritual service is not to pray but to present ourselves as a living sacrifice to God. When we consecrate ourselves to the Lord, we are to become absolute in our walk with Him. To be a living sacrifice simply means to present yourself to the Lord while you are still living.
Romans 12:1
I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service.
If one should notice struggle going when trying to do some spiritual things, it simply means that the person is not consecrated to the Lord absolutely. If there is sin, dispositional traits and reservations in the person's life, such a person cannot achieve absolute consecration. There are certain things that may happen to us until we absolutely consecrate ourselves to God.
God wants us to be absolute in our service and walk with Him. It may require us to consecrate ourselves afresh to Him. As believers we don't live in the flesh, instead we are to remain yielded to the leadership of God's Spirit daily.