Commentaries:
Robertson's Word Pictures (NT)
Save by prayer (ei mh en proseuxh). The addition of "and of fasting" does not appear in the two best Greek manuscripts (Aleph and B). It is clearly a late addition to help explain the failure. But it is needless and also untrue. Prayer is what the nine had failed to use. They were powerless because they were prayerless. Their self-complacency spelled defeat. Matthew 17:20 has "because of your little faith" (oligopistian). That is true also. They had too much faith in themselves, too little in Christ. "They had trusted to the semi-magical power with which they thought themselves invested" (Swete). "Spirits of such malignity were quick to discern the lack of moral power and would yield to no other" (ibid.).
Other Robertson's Word Pictures (NT) entries containing Mark 9:29:
Mark 9:14
DISCLAIMER: Church of the Great God (CGG) provides these resources to aid the individual in studying the Bible. However, it is up to the individual to "prove all things, and hold fast to that which is good" (I Thessalonians 5:21). The content of these resources does not necessarily reflect the views of CGG. They are provided for information purposes only.