Recently, in studying and teaching through the life of Saul, I noticed the similarity of these two verses. The first is from Samuel's farewell address in 1 Samuel 12. The second is from the apostles' instructions to the church to choose deacons to carry out the work of ministry.
Moreover, as for me, far be it from me that I should sin against the LORD by ceasing to pray for you; but I will instruct you in the good and right way (1 Samuel 12:23).
But we will devote ourselves to prayer and to the ministry of the word (Acts 6:4).
In both cases we see a commitment to prayer and a commitment to the ministry of teaching the truth.
All spiritual leaders, whether pastors or dads or Bible study teachers or whatever other relationship one might be in would do well to grasp the necessity of prayer and the teaching of the word.
To do less is to "sin against the Lord."