Saul has been listening to all this and he recognises David's voice. ‘And Saul knew David's voice, and said,’ – these are the same words as the previous incident about two or three years before (1 Samuel 24:16) – ‘is this thy voice my son David?’ In what way was David his son? He was his son-in-law, but Saul had given away his wife to someone else.
Emotion does not last and it is not to be trusted when it is divorced from the mind. The person who hands themselves over to their emotions and allows them to rule over him does not really know himself. Such people tend to believe their own emotions too much, and to enjoy being carried away by them. But strong emotions in one direction on one day can change to strong emotions in another direction on another day – it is highly unstable. The mind must be in charge, however strongly the emotions are stirred, and every thought must be submitted to a conscience which is governed by the word of God.