Today is the feast of Sts. Simon and Jude, so it has its own proper Gospel.
But the Gospel reading for the weekday is the one where Jesus tells us to enter through the narrow gate. The English translation uses the word "strive"--"strive to enter through the narrow gate."
Actually, though, the original Greek text here has a stronger verb: agonizomai.
If it reminds you of the word "agony," it should, because it's related. It doesn't just mean to strive in a non-committal sort of way. Instead, it means to struggle, or to fight, or to compete in an athletic contest.
So Jesus is telling us that we have to really challenge ourselves and work hard to enter through the narrow gate that leads to eternal life.