As we just heard in today's Gospel, some people, to test Him, asked Jesus for a sign, some miracle from heaven. They did so because they didn't recognize God's presence in the person of Jesus. So, they believed that if He performed some sign on demand, it would prove God was with Him.
In truth, God was powerfully at work in Jesus' ministry, but the people lacked eyes of faith to see it. There was no need for miracles for the people to accept His message. As Jesus would later say to Thomas after the Resurrection, "Blessed are they who have not seen and have believed." [John 20:29]
Sometimes, even people of faith can be enticed to seek "signs and wonders." We can fail to see that the LORD is present among us in and through the goodness, kindness, mercy, love, and hospitality of others, in all kinds of ordinary expressions of love, even in people's quiet prayerfulness.
We can miss the divine presence in the everyday and the familiar. The great Irish patriot and poet Joseph Mary Plunkett wrote of Jesus, "I see His blood upon the rose and in the stars the glory of His eyes." Nature spoke to him of Christ. The best of human nature and our relationships with one another can also speak to us of God.