To understand the work of apostles we need to look at the bits and pieces of evidence Paul supplies in his epistles.
Check out Colossians 1:24-29
Galatians 4:19With apostolic input and impartation the labor shifts from the people to the apostle: he labors on their behalf and once they receive his impartation as a catalyst their spiritual growth no longer requires so much effort because it grows from within like a plant! The mystery is Christ within that gives us hope to obtain that glory promised to us!

Though now we grown and fight to keep the faith there is an indomitable force within us that will never stop urging us on and on until we overcome everything that prevents us from growing: every evil force must give way to the natural growth of the saint like the hard soil has to give way to the plant breaking through the surface!

As the worm keeps on struggling to materialize the dream that it can fly it spins itself into cocoon. Even in the cocoon the worm keeps on struggling to make that dream come true and during the maintained action in the darkness and seclusion of the cocoon it suddenly sprouts wings and develops teeth to eat through the cocoon and to appear as a beautiful butterfly!

In the same way as we allow the work of the Holy Spirit to produce Christ within us by accepting the labors of the apostles and prophets on our behalf we suddenly sprout wings and our nature changes ? effortlessly!

1753 energeia { en-erg?-i-ah}

from 1756; TDNT – 2:652,251; n f

AV – working 4, effectual working 2, operation 1, strong 1; 8

GK – 1918 { ejnevrgeia }

1) working, efficiency
1a) in the NT used only of superhuman power, whether of God or of the Devil

For synonyms see entries 970, bia; 1411, dunamis; 1849, exousia; 2479, ischus; and 2904, kratos.
See entry 5820 for comparison of synonyms.

This is a superhuman effort on behalf of the apostles ? not the saints! Apostles take the strain on behalf of the saints and when they are received God releases a spiritual energy that changes believers into saints! This is the mystery: by the labors of apostles and other five fold ministries Christ is formed in lives of those who believe their words.

Hebrews 2:4
4 God also bearing witness both with signs and wonders, with various miracles, and gifts of the Holy Spirit, according to His own will?

Hebrews 4:2
2 For indeed the gospel was preached to us as well as to them; but the word which they heard did not profit them, not being mixed with faith in those who heard it.

This activity will be shown in the lives of saints: their actions will begin to change if they receive the words preached by faith: in other words if they believe God is speaking to them through the chosen vessel.
1411 dunamis { doo?-nam-is}

from 1410; TDNT – 2:284,186; n f

AV – power 77, mighty work 11, strength 7, miracle 7, might 4, virtue 3, mighty 2, misc 9; 120

GK – 1539 { duvnami' }

1) strength power, ability
1a) inherent power, power residing in a thing by virtue of its nature, or which a person or thing exerts and puts forth
1b) power for performing miracles
1c) moral power and excellence of soul
1d) the power and influence which belong to riches and wealth
1e) power and resources arising from numbers
1f) power consisting in or resting upon armies, forces, hosts