In the first reading today (1 Sm 3:3b-10, 19), we hear God calling Samuel. It's important for many of us that God kept trying. God reached out over and over, even though Samuel didn't catch on at first. In fact, it took another person to clue him in to what was going on, that it was God calling him, not Eli. God just hit redial and kept waiting until Samuel picked up.
In the Gospel (Jn 1:35-42), John leads Andrew to Jesus, and Andrew leads Simon. Again, like with Eli and Samuel, we see the message being passed along. Jesus would have literally passed on by without someone to point him out. God is the light, and we are mirrors able to reflect it to others, so they too can see.
Further, though it isn't explicitly seen in today's Gospel reading, we know that those apostles needed more than one chance. Simon "The Rock", in fact, has a history in the Gospels of messing things up, but God never let him go. God never gives up on us. Like He did with Samuel and later the apostles, and so many others, God keeps calling back until we recognize Him and answer.
Speak, Lord, for your servant is listening.