17 But you say, he kissed the Lord. Yes, he kissed Him indeed with his lips. The Jewish people has this kiss, and therefore it is said: “This people honours Me with their lips, but their heart is far from Me.” So, then, he who has not faith and charity has not the kiss, for by a kiss the strength of love is impressed. When love is not, faith is not, and affection is not, what sweetness can there be in kisses?
Source: Letters (New Advent)