“Unto me, who am less than the least of all saints, is this grace given, that I should preach among the Gentiles the unsearchable riches of Christ;”  
Ephesians 3:8

It is good we pay attention to the uniqueness of the grace mentioned in the main verse “to preach among unbelievers the unsearchable riches of Christ”; this is beautiful. Not to preach among them their sinful nature, or the fact that they will only know sin and repentance but the riches of Christ; the glories made available to them, the Apostle said he had the grace to communicate these realities to unbelievers and they’d understand faster and better- the working of such grace- than if someone else did. There is such a grace to communicate and he expects us to express this grace with diligence:
“Having then gifts differing according to the grace that is given to us… he that teacheth, on teaching;” Romans 12:6-7
He emphasized this grace again to the church at Rome:
“Nevertheless, brethren, I have written the more boldly unto you in some sort, as putting you in mind, BECAUSE of the grace that is given to me of God…” Romans 15:15
It’s not enough to be conscious of the grace of God at work in and with you, you ought to be active with that grace- grace when matched with labor expresses itself in bountiful incalculable results:
“But by the grace of God I am what I am: and his grace which was bestowed upon me was not in vain; but I laboured more abundantly than they all: yet not I, but the grace of God which was with me.”  1 Corinthians 15:10