John Owen gets to the rub of pastoral ministry in The True Nature of a Gospel Church:
The second duty of a pastor towards his flock, is, continual fervent prayer for them. 'Give ourselves unto the word and prayer.' Without this, no man can or doth preach to them as he ought, nor perform any other duty of his pastoral office. From hence may any man take the best measure of the discharge of his duty towards his flock. He that doth constantly, diligently, fervently pray for them, will have a testimony in himself of his own sincerity in the discharge of all other pastoral duties; nor can he voluntarily omit or neglect any of them. And as for those who are negligent herein, be their pains, labour, and travail in other duties never so great, they may be influenced from other reasons, and so give no evidence of sincerity in the discharge of their office. In this constant prayer for the church, which is so incumbent on all pastors, as that whatever is done without it, is of no esteem in the sight of Jesus Christ.Those who neglect the ministry of word and prayer - regardless of their tenacity in other labors - can have no assurance as to the faithfulness of their ministry. Whatever else you do, whatever else you sacrifice, if it is lacking in prayer, it is "of no esteem in the sight of Jesus Christ" - and, to be clear, His is the only esteem that actually matters.
Owen concludes with the simple challenge of whether we actually believe the Gospel we have been installed to minister:
To preach the word therefore, and not to follow it with constant and fervent prayer for its success, is to disbelieve its use, neglect its end, and to cast away the seed of the gospel at random.See Owen, Works, vol. 16, p. 78.
I ask myself - and encourage everyone who ministers, in or out of church office - how do we measure the discharge of our duties and faithfulness of our roles? By personal labor or by personal prayer? Not an unimportant question.