The one who prepares the way for Al-Masih
The Prophet Yahya (John) was commanded by Allah to proclaim to the people: “Repent and be baptized so that Allah may forgive you your sins.” Many people came to Prophet Yahya to be baptized by him. Some mistakenly thought that the Prophet Yahya was Al-Masih, whom they had been waiting for.
Nabi Yahya set them straight, saying: “I baptize you with water. but the One who is much greater than me will come. He will baptize you with Al-Ruhul Qudusu (the Holy Spirit) and fire. I am not worthy even to untie the straps of His shoes for Him.”
The main mission of the Prophet Yahya was to “prepare the path to believe in Al-Masih”.
The Prophet Zakariya pronounced the words of Allah over him: “He will call him the Prophet of the Most High because he will go ahead. and prepare a way for God.”
Isa is Al-Masih whom everyone had been waiting for, and the Prophet Yahya was the one whom Allah has sent to "prepare the way" for Him.