Albert Barnes on Luke 14:19

I go to prove them. To try them, to see if he had made a good bargain. It is worthy of remark that this excuse was very trifling. He could as easily have tried them at any other time as then, and his whole conduct shows that he was more disposed to gratify himself than to accept the invitation of his friend. He was selfish; just as all sinners are, who, to gratify their own worldliness and sins, refuse to accept the offers of the gospel.