God the Spirit is the One whom the Son has given to us. When God is given to us, He becomes the Spirit in us. This Spirit is the consummation of the Triune God as the Father, the Son, and the Spirit. As the totality of the Triune God, this Spirit is dwelling in us as the life-giving Spirit.
When this Spirit enters into us, He regenerates us (John 3:5-6). Through regeneration, the Spirit comes into us to make us another person. This same Spirit, after regenerating us, becomes life in us. Now, we are persons who are mingled with God. Wherever we go, we are persons who are one with God. If we realize this, we will never say that we are weak.
The above three passages speak of the three steps taken by the three persons of the Trinity. They speak of the Father's dispensing, the Son's dispensing, and the Spirit's dispensing. Eventually, when the Spirit comes, He becomes the very life in our regenerated being. This regenerated being is the mingling of the Triune God with us.
The result of this dispensing is to make men of dust stones for the divine building (John 1:42).
God the Father is expressed in the Son. This is fully revealed in John 14:7-11. There the Son said that if we have seen Him we have seen the Father (v. 9). The Son is in the Father, and the Father is in the Son (vv. 10-11). The Two are one (John 10:30). This is for the expression of the Father in the Son.
In John 14:16-17a, the Lord Jesus told us that the Spirit as the third person of the Godhead is the reality of the second. The first person, God the Father, is expressed in the second, God the Son. Now the third person, the Spirit, is realized as the reality of the Son. Hence, the third person is the reality of the second. The Father is expressed in the Son, and the Son is realized as the Spirit. When the Spirit comes, the Son is here, and when the Son is here, the Father is here also. As long as we have the Spirit, we have all of the Three.