This comes from E.M. Bounds classic prayer text, “Purpose in Prayer,” and is a quote from a 16th century pastor, John Welch:
Pray for your pastor. Pray for his body, that he may be kept strong and spared many years. Pray for his soul, that he may be kept humble and holy, a burning and shining light. Pray for his ministry, that it may be abundantly blessed, that he may be anointed to preach good tidings. Let there be no secret prayer without naming him before your God, no family prayer without carrying your pastor in your hearts to God.
There is no greater gift you could offer these shepherds.