To understand what the 1st reading is talking about, it would be necessary to read the Book of Numbers where Balaam, makes his first appearance.
Although Balaam was not a Jew, he was considered a prophet of God, for he hears the word of God, he sees what God makes him see, and that he receives an answer from God.
But he was engaged by the enemies of Israel to lay a curse on Israel. So although he was a prophet, he too could be bought at a price to do something that could be against God.
Balaam had intended to curse Israel, but he couldn't do it and instead he changed his curse into a blessing for Israel.
And in that blessing, he even prophesied about "the star of Jacob" who would take the leadership, and that a sceptre rises from Israel.
Even though he was a prophet of God, he did not always live up to his faithfulness to God as later he would conspire with the enemies of Israel to lead Israel astray and become unfaithful to God.
In the gospel, we hear of another prophet that was brought up for discussion by Jesus when He was questioned about His authority.
John the Baptist was not just another prophet, but he was considered the "greatest" of all the prophets because it was he who identified and pointed out who the Saviour was.
The people all knew that, including the chief priests and the elders, and that was why Jesus brought him up for the discussion on authority, because John the Baptist had proven that he was a true prophet of God.
May we also prove to be true prophets of God by being a blessing for others and Jesus has given us the authority to do so.