Samson’s secret lay (primarily) in his long hair. That was one of the elements of his Nazariteship. Just as long hair in women represents glory or honor (1 Corinthians 11:15), so it is the opposite in men. For men, long hair is not glory, but is without honor.
1 Corinthians 11
14 Or does not nature itself teach you that if a man has long hair, it is a dishonor to him?
without honor
The Greek word (atimia) translated here as dishonor is translated as “shame” in other translations. But it literally means no-honor, or: without honor. For men, there is no honor in having long hair, unlike for women. The long hair that Samson wore is a picture of the coming of the Lord Jesus in humiliation, without honor. It is a picture of submission to His Father.
Power
But long hair in Scripture is also a picture of power, of the works of man. Hair on the head speaks of the power of thought, pubic hair of potency, etc. It speaks of that which the flesh produces. Long hair is a covering (1 Cor. 11:15) and a picture of the law, which was, after all, imposed on the flesh. Samson’s long hair speaks of Him who came under the law, in the flesh, even in the likeness of sinful flesh, though he did not sin (Heb. 4:15):
Galatians 4
4 But when the fullness of the time had come, God sent forth His Son, born of a woman, born under the law.
Romans 8
3 For what the law could not do, in that it was weak through the flesh, God, sending His own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh.