The ministry may be difficult, because it is utterly contrary to fallen human nature:

¹⁸ For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who by their unrighteousness suppress the truth. ¹⁹ For what can be known about God is plain to them, because God has shown it to them. ²⁰ For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse. ²¹ For although they knew God, they did not honor him as God or give thanks to him, but they became futile in their thinking, and their foolish hearts were darkened. ²² Claiming to be wise, they became fools, ²³ and exchanged the glory of the immortal God for images resembling mortal man and birds and animals and creeping things.

²⁴ Therefore God gave them up in the lusts of their hearts to impurity, to the dishonoring of their bodies among themselves, ²⁵ because they exchanged the truth about God for a lie and worshiped and served the creature rather than the Creator, who is blessed forever! Amen. Romans 1:18–25 (ESV)

Indeed, without some work of God, there cannot even be an expectation that the message will be received:

The natural person does not accept the things of the Spirit of God, for they are folly to him, and he is not able to understand them because they are spiritually discerned.  1 Corinthians 2:14

Since the Christian proclamation is something which is unpalatable to a human being by nature, rejection should be expected:

18 “If the world hates you, know that it has hated me before it hated you. 19 If you were of the world, the world would love you as its own; but because you are not of the world, but I chose you out of the world, therefore the world hates you. 20 Remember the word that I said to you: ‘A servant is not greater than his master.’ If they persecuted me, they will also persecute you. If they kept my word, they will also keep yours. 21 But all these things they will do to you on account of my name, because they do not know him who sent me. 22 If I had not come and spoken to them, they would not have been guilty of sin, but now they have no excuse for their sin. 23 Whoever hates me hates my Father also. 24 If I had not done among them the works that no one else did, they would not be guilty of sin, but now they have seen and hated both me and my Father. 25 But the word that is written in their Law must be fulfilled: ‘They hated me without a cause.’ John 15:18-25

Indeed, we should not expect otherwise:

²⁰ And he lifted up his eyes on his disciples, and said: “Blessed are you who are poor, for yours is the kingdom of God. ²¹ “Blessed are you who are hungry now, for you shall be satisfied. “Blessed are you who weep now, for you shall laugh. ²² “Blessed are you when people hate you and when they exclude you and revile you and spurn your name as evil, on account of the Son of Man! ²³ Rejoice in that day, and leap for joy, for behold, your reward is great in heaven; for so their fathers did to the prophets.

²⁴ “But woe to you who are rich, for you have received your consolation. ²⁵ “Woe to you who are full now, for you shall be hungry. “Woe to you who laugh now, for you shall mourn and weep. ²⁶ “Woe to you, when all people speak well of you, for so their fathers did to the false prophets.  Luke 6:20-26

With that background, we are in a position to evaluation Bridges’s discussion of difficulty:

From the difficulties with the world—unfaithfulness to our Master furnishes the only “way of escape.” [This is an ironic use of the phrase (1 Cor. 10:13); the temptation is to escape from the difficulty with the world – which is in itself no escape, because it would be to run into the displeasure of God.] The subject-matter of our commission is truth, that comes into immediate contact with latent and deep rooted prejudices. The strongest feelings of a proud nature are brought into constant play against our unwelcome tale: so that we “become the enemy,” instead of the friend, of our fellow-sinners, “because we tell them the truth.”  The sacrifices, which in our Master’s name we demand of the cherished objects of misplaced affections; the exhibition of heavenly pleasures, (far nobler in their character, and more permanent in their enjoyment, yet most distasteful to the natural mind) ; the certain endurance of reproach in the service of the Gospel—these component parts of our commission, even from the voice of the most alluring charmer, excite the enmity of the carnal mind to our message, and to the messenger for his work’s sake.

Does this mean that we are any better than others? No. Eph. 2:3, “like the rest of mankind.” Here is where a sturdy understanding of and innate depravity and election make space for humility:  I could not and would have heard this message, but for the grace of God. Therefore, when I am rejected by another, he is doing merely what I would have – and did do – myself. A good doctrinal grounding makes sense of the rejection and creates a ground on which we can love and pity our fellow human being and respond in grace to the rejection we will often receive. It is not for nothing that Jesus continued in Luke 6 as follows:

²⁷ “But I say to you who hear, Love your enemies, do good to those who hate you, ²⁸ bless those who curse you, pray for those who abuse you. ²⁹ To one who strikes you on the cheek, offer the other also, and from one who takes away your cloak do not withhold your tunic either. ³⁰ Give to everyone who begs from you, and from one who takes away your goods do not demand them back. ³¹ And as you wish that others would do to you, do so to them. Luke 6:27–31 (ESV)

This also makes sense of Paul’s instruction to Timothy: Note that in context, “youthful lusts” is not a reference to sexual lust, but rather to wrangling:

²² So flee youthful passions and pursue righteousness, faith, love, and peace, along with those who call on the Lord from a pure heart. ²³ Have nothing to do with foolish, ignorant controversies; you know that they breed quarrels. ²⁴ And the Lord’s servant must not be quarrelsome but kind to everyone, able to teach, patiently enduring evil, ²⁵ correcting his opponents with gentleness. God may perhaps grant them repentance leading to a knowledge of the truth, ²⁶ and they may come to their senses and escape from the snare of the devil, after being captured by him to do his will. 2 Timothy 2:22–26 (ESV)