a. To maintain the Christian life is a very difficult thing, requiring the observance of many rules.
b. The same. Emphasis is placed on difficulty of remaining a Christian. Discouraging prospect. Everything depends on your holding on to Gods hand. Impression given that God doesn't care too much if you let go. "Keep up your speed" or "gravity" will cause you to come "crashing down" (a popular presentation).
c. Everything depends on your believing that God loves, respects, and values you so much that He is holding on to your hand. What makes Christian life appear difficult is eclipse of message of Christ's righteousness. "The love of Christ constraineth us" and makes self-centered living "henceforth" impossible.