The finished work of Christ was when He suffered on the Cross to take upon Himself the guilt and punishment of our sin. It took three hours of suffering to achieve the completion of God's plan of salvation for mankind. That is the reason why at the end of the three hours, Jesus said, "It is finished!" and then gave up HIs spirit to the Father.
The preaching of the Gospel by the Apostles was to announce and declare what Jesus did for them on the Cross and that He can do the same for their hearers.
Therefore He is also able to save to the uttermost those who come to God through Him, since
He always lives to make intercession for them. Hebrews 7:25
Then there is His return where He fights and removes the wicked, raises the dead in Christ, and catches up those who are alive and remain.
Behold, the day of the LORD is coming,
And your spoil will be divided in your midst.
For I will gather all the nations to battle against Jerusalem;
The city shall be taken,
The houses rifled,
And the women ravished.
Half of the city shall go into captivity,
But the remnant of the people shall not be cut off from the city.
Then the LORD will go forth
And fight against those nations,
As He fights in the day of battle.
And in that day His feet will stand on the Mount of Olives,
Which faces Jerusalem on the east.
And the Mount of Olives shall be split in two,
From east to west,
Making a very large valley;
Half of the mountain shall move toward the north
And half of it toward the south.
Then you shall flee through My mountain valley,
For the mountain valley shall reach to Azal.
Yes, you shall flee
As you fled from the earthquake
In the days of Uzziah king of Judah.
Thus the LORD my God will come,
And all the saints with You.
Zechariah 14:1-5
Then He judges His people, at the judgement seat of Christ.
For we must all appear before the judgment seat of Christ, that each one may receive the things done in the body, according to what he has done, whether good or bad. 2 Corinthians 5:10
There is much left for our Lord to do, before He enters His rest.
JLB