Most people believe that the starting point of all of the redemptive events began at the cross.
The majority of believers today would say that all of the inheritances that were promised, eternal life and salvation etc, began at the cross. After all Christ Himself said "It is finished."
They also believe that these things are finished but yet we still wait for the final culmination at the end of the world or at the end of our life. They will basically refer to the "already but not yet" principle and say that it has been stretched out for nearly 2000 years now.
But the truth is that the "already but not yet" period actually only spanned from Christ's ministry until His second coming in judgement upon the Old Covenant world. A few examples with some quick comments...
"Verily, verily, I say unto you, The hour is coming, and now is, when the dead shall hear the voice of the Son of God: and they that hear shall live." John 5:25
The hour is coming and also now is. How is that even possible? It's coming but it also now is? Well it is possible because of the transitional 40 year "already but not yet" period. This was the period called "the last days" when the Old Covenant Age was coming to a close and the New Covenant Age was blooming and ready to burst into full maturity.
"But the hour is coming, and now is, when the true worshipers will worship the Father in spirit and truth, for the Father is seeking such people to worship him." John 4:23
Again, already but not yet fully consummated. Now check this out. Written AFTER the cross...
"That your sins may be blotted out, WHEN the times of refreshing shall come from the presence of the Lord; and he shall send Jesus Christ.. whom the heaven must receive UNTIL the times of restitution of all things..."
Again, the work had been done on the cross however the final realization and inheritance of salvation wouldn't be until the end of the age. Again, written AFTER the cross...
"For now is our salvation nearer than when we believed." Romans 13:11
How could it be nearer than when they first believed? If they already possessed it, it can't get any closer!
Look what Paul says in Ephesians chapter 1...
In Him you also trusted, after you heard the word of truth, the gospel of your salvation; in whom also, having believed, you were sealed with the Holy Spirit of promise, 14 who[b] is the guarantee of our inheritance until the redemption of the purchased possession, to the praise of His glory.
When Paul spoke of the resurrection he said...
"And He raised us up with him and seated us with him in the heavenly places in Christ Jesus." Ephesians 2:6
But at the same time Paul also said that the dead wouldn't be raised up until the coming of the Lord to usher in the new age. Yet here he refers to it as an already accomplished act. Why? Because it was so close and it was as good as done at that point.
The true "already but not yet" principle should only be applied to the 40 year transitional period between the Old and New Covenants.