Jesus wanted the crowds to think before they followed. Many were going along with Him (Luke 14:25), and He had just said that following Him would mean putting Him above family and even one's own life (Luke 14:26-27). The question asks each listener to picture a builder who plans before he starts. Barnes draws the lesson: "Every man who becomes a follower of Jesus should calmly and deliberately look at all the consequences of such an act and be prepared to meet them."

No one in the crowd replies. Jesus answers His own question by describing what happens to the builder who does not plan: he lays the foundation, "is not able to finish it," and "all that behold it begin to mock him, Saying, This man began to build, and was not able to finish" (Luke 14:29-30). He adds a second picture, a king weighing his army before battle (Luke 14:31-32), and then draws the point: "whosoever he be of you that forsaketh not all that he hath, he cannot be my disciple" (Luke 14:33).

Barnes explains that a tower was "a place of defense or observation, erected on high places or in vineyards," built high so a watchman could see an enemy coming. It was a costly project that could stand half-finished for everyone to see.

The word "counteth" translates psephizo, which Thayer defines as "to count with pebbles, to compute, calculate, reckon." Pebbles were used for counting, so the picture is of someone sitting down and working out the sums. The word appears in only one other New Testament verse, Revelation 13:18.

Jesus did not hide the cost of following Him. Instead of making discipleship sound easy to gain a larger crowd, He asked the crowd to weigh it honestly. Barnes writes, "Religion is a work of soberness, of thought, of calm and fixed purpose."

The commentators read the tower a little differently. Gill likens it to a public profession of faith: "Taking up a profession of Christ and his Gospel, is like building a tower." Matthew Henry's Concise Commentary says "we must consider the expenses of our religion" and "we must consider the perils of it." Barnes adds that we must resolve "by the grace of God" to fulfil its requirements. The cost is real, but the strength to finish comes from God.