There are some powerful connections between the first reading and the Gospel in today's Mass, and that Responsorial Psalm is the kind of prayer that you hold onto when you hear things like that.
To put it mildly, I don't even like today's Gospel. When I was preparing for the liturgy by reading the texts last night, I saw what the Gospel was and couldn't stop the "ugh." from escaping my lips. You know what it is? It's one of those passages that we hear not once during the liturgical year, but three times, in all its creepy detail. (Granted, one of those times is on the feast of the Beheading of John the Baptist.)
What was John's crime? He was simply carrying out what the first reading exhorts all Christians: "Let marriage be honored among all, and the marriage bed kept undefiled" (Heb. 13:4).
Timely, isn't it?