The plan of salvation was an eternal purpose in the mind and heart of the Triune God prior to the creation of the earth. The work of salvation was prefigured and promised throughout the Old Testament. The work of salvation is accomplished through the whole work of the Lord Jesus through the Spirit and in obedience to the Father.
Salvation, which is the primary vocation of the second person of the Trinity, is a seamless project spanning from his birth to his interminable intercession. It is right to talk of the saving obedience of Jesus in his thirty-three years prior to the cross. It is appropriate to speak of an efficacious and saving resurrection, for apart from it there would be no salvation.
Is it correct however to speak of a saving ascension and saving intercession? I think so. Scripture testifies to the fact that the entrance of God into heaven on our behalf and his continued presence there is foundational for our eternal salvation (Heb 7:25, 9:24, Rom 8:34).
The diagram below illustrates the point. The earthly work of Jesus prior to the cross is necessary for the work of the cross to be adequate and sufficient. Without the perfect obedience of Christ there would be no perfect sacrifice and with no perfect sacrifice there would be no propitiation, forgiveness, or imputed righteousness. The heavenly work of the Son flows forth from the cross and is grounded in the cross. There would be no resurrection, ascension or intercession apart from the cross.
The exaltation of Christ came as a result of his humiliation. The resurrection was a vindication of the work of the cross. The ascension and the intercession of Christ are both rooted in his work on the cross as he enters into heaven to present himself before the Father as the indestructible High Priest who will forever intercede on our behalf that we might have eternal salvation.
The cross is the center of the saving work but cannot be separated from what precedes or what follows. The entire life of Christ is the saving work of God on our behalf. Remove one element and our salvation falls apart. This is true if you remove incarnation, perfect obedience, resurrection, ascension, and intercession. Jesus is our whole and complete Savior. All that He has done, is doing, and will continue to do is necessary for us to be rescued.