There are tremendous differences between "motivational speaking" and "biblical preaching." In America today, many churches offer one or the other. One approach leaves people "encouraged" in their emotions and in their "self-esteem." The other builds up Christians in the Gospel as the Holy Spirit applies the Scriptures to the hearts and minds of the hearers.
Motivational speakers tell a lot of stories and seek to sway through emotion and pop psychology. Biblical preachers tell some stories, but above all seek to have people influenced by the Holy Spirit through the Word of God. Motivational speakers may or may not throw in a few Bible verses to "salt" their main topic. Biblical preachers rely totally upon the Scriptures to "drive" the content and to feed God's sheep. The Bible is the basis of their message.