But it's more than just agreeing with God. You can agree with Him and His Word all you want, and not take any action. Not that deeds are a means of salvation, but they flow out of having received Grace, being at one with God, and having a heart to do His will. Faith without works is dead, right? So sanctification (the process of being made holy) can't spring solely out of being in agreement with the Almighty. There has to be action springing out of having received Grace so we can pass it on to others. Now don't go and do something rashly just because I said we need to take action. Make sure that what you are doing is in accordance with God's will, and act in His wisdom, not your own.
But I still agree with you. Being in agreement with God is what justifies (saves) us.