The distinction between the active and passive obedience is not a distinction of periods. It is our Lord’s whole work of obedience in every phase and period that is described as active and passive, and we must avoid the mistake of thinking that the active obedience applies to the obedience of his life and the passive obedience to the obedience of his final sufferings and death.
The real use and purpose of the formula is to emphasize the two distinct aspects of our Lord’s vicarious obedience. The truth expressed rests upon the recognition that the law of God has both penal sanctions and positive demands. It demands not only the full discharge of its precepts but also the infliction of penalty for all infractions and shortcomings. It is this twofold demand of the law of God which is taken into account when we speak of the active and passive obedience of Christ. Christ as the vicar of his people came under the curse and condemnation due to sin and he also fulfilled the law of God in all its positive requirements. In other words, he took care of the guilt of sin and perfectly fulfilled the demands of righteousness. He perfectly met both the penal and the preceptive requirements of God’s law. The passive obedience refers to the former and the active obedience to the latter. John Murray, Redemption -Accomplished and Applied, pp. 20-22.
Jesus' “passive” and “active” obedience were lifelong aims as he fulfilled both the demands and suffered the penalties of God’s law, both of which culminated in the cross.