Now unto him that is able to do exceeding abundantly above all that we ask or think, according to the power that worketh in us,
Note 15 at Eph 3:20: Many use only the first part of this verse and omit "according to the power that worketh in us." That changes the whole meaning. It is not true that God will do exceeding abundantly above all that we ask or think, period. He has that power, but this verse ties the use of His ability to the power that works in us. No power working in us means there will be no power of God coming through us.
Jesus told us in Ac 1:8 of the power that we would receive when the Holy Ghost comes upon us. Ro 1:16 says the Gospel is the power of God unto salvation (see note 1 at that verse). However, Christ is called the power of God (1Co 1:24), and in context (Christ dwelling in our hearts, Eph 3:17), this is Paul's probable meaning here. The power of God could also be referring to all the operation of God in our lives including Christ, the power of the Holy Ghost, faith, the Word, love, etc.