It doesn't look like good news for the gospel when the senior pastor of one of the world's largest Christian congregations is convicted of corruption.

As this website has reported, David Yonggi Cho, founder of the million-strong Yoido Full Gospel Church in Seoul, South Korea, has been found guilty of embezzling $12 million in church funds. He was sentenced to three years in prison – suspended for five years – and ordered to pay $4.67 million in fines.

As a report by the Gospel Herald put it, the news "spread like wildfire among global Christian communities, where followers of the disgraced South Korean mega-church pastor searched for an explanation of how their spiritual leader became entangled in the crime".

Perhaps, however, we should not be so surprised. Christian leaders are no more immune from temptation than anyone else – and it is often money, sex or power which trips them up. Yet the New Testament sets a high standard for those who aspire to have oversight of congregations, declaring that they "must be blameless – not overbearing, not quick-tempered, not given to drunkenness, not violent, and not pursuing dishonest gain," as Paul puts it in his Epistle to Titus. Rather, they must be "hospitable, love what is good... [and] self-controlled, upright, holy and disciplined". (Titus 1v7-8)

Nonetheless, Paul himself was the first to admit that sin was an ongoing struggle for him: "I have the desire to do what is right, but not the ability to carry it out," he laments in Romans 7. "For I do not do the good I want, but the evil I do not want is what I keep on doing." Although some have argued he was speaking about his experience before becoming a Christian, the majority of Bible scholars – from Augustine through to the Reformation and beyond – agree that he was writing about his ongoing post-conversion struggle against sin. More recently, when Pope Francis was asked to define himself, he replied: "I am a sinner. This is the most accurate definition. It is not a figure of speech, a literary genre. I am a sinner."

Church leaders are not expected to be perfect – but they are expected to be living in daily repentance and faith. The problem for them comes when the daily battle against sin is abandoned, when it remains unconfessed to God, and when sin makes it impossible for them to discharge the duties of their ministry or brings the gospel into public disgrace.

In the case of David Yonggi Cho, one of his church elders has said: "Over the past 14 years, I have met with Rev Cho many times to try to persuade him to repent and return to being a great pastor, but the corruption has continued. That's why I had no choice but to disclose it to the outside world."

Sometimes, on the other hand, ministers are brought down by untrue accusations – or the misdeeds of others. Again, Paul wrote of experiencing "glory and dishonour, bad report and good report" and of his mission team being "genuine, yet regarded as impostors," (2 Corinthians 6v7-9). In Cho's case, one American minister and friend, Bob Rodgers, has suggested his downfall was at least in part due to naïvety in signing financial papers prepared by others without reading them properly.

Either way, the loneliness and lack of accountability which many church leaders experience makes them even more vulnerable to the temptations of Satan who is – after all – constantly seeking their downfall. Who are your church ministers? What could you pray for them each day? And what words of encouragement could you offer them today?