Explanation of 1 Thess 2.3 Paul's Proclamation in Thessaloniki

1Th 2:3  For our preaching was not grounded on a delusion, nor prompted by mingled motives, nor was there fraud in it. 

Notes: For our preaching was not grounded on a delusion,

Preaching : Paraklesis = a calling near, exhortation. Really here it means a calling to one's side for admonition, encouragement and comfort. Thayer 5)persuasive discourse, stirring address

5a) instructive, admonitory, conciliatory, powerful hortatory discourse

Paul Preaching

a) was not grounded on a delusion [WNT ]or error [KJV]; It was not prompted by deceit; i.e. (plano) = designed to lead astray, to beguile.  There was a correctness of message and purity of life to back it up.

b)nor prompted by mingled motives,  nor impure motives; KJVNor of uncleanness (oude ex akatharsias). “This disclaimer, startling as it may seem, was not unneeded amidst the impurities consecrated by the religions of the day” (Lightfoot). There was no necessary connection in the popular mind between religion and morals. The ecstatic initiations in some of the popular religions were grossly sensual. RWP

"It was such as to lead to holiness and purity. The apostle appeals to what they knew to be the tendency of his doctrine as an evidence that it was true. Most of the teaching of the pagan philosophers led to a life of licentiousness and corruption." Barnes Notes on the NT

c)nor was there fraud in it. (nor are we trying to trick you NIV)

Not by the arts of deceit. There was no craftiness or trick, such as could not bear a severe scrutiny. No point was carried by art, cunning, or stratagem. Everything was done on the most honorable and fair principles. It is much when a man can say that he has never endeavored to accomplish anything by mere trick, craft, or cunning. Sagacity and shrewdness are always allowable in ministers as well as others; trick and cunning never. Yet stratagem often takes the place of sagacity, and trick is often miscalled shrewdness. Guile, craft, cunning. imply deception, and can never be reconciled with that entire honesty which a minister of the gospel, and all other Christians, ought to possess; see notes on 2Co 12:16  If I love you so intensely, am I the less to be loved? Be that as it may: I was not a burden to you. But being by no means scrupulous, I entrapped you, they say! 

2Co 12:17  Have I gained any selfish advantage over you through any one of the messengers I have sent to you? Barnes Notes.

Was there any improper means: plausible but insincere methods of making converts among the Thessalonians; suppression of the truth, adulterating the Word of God for gain or popularity.