In the video, Pacquiao, 42, professed his faith by expressing gratitude to God and said his boxing career would not have been possible without the Lord.
Pacquiao, who became a pro-boxer in 1995, holds the record as the only boxer to hold 12 world titles in four different decades. Pacquiao is also the oldest fighter to win a world title and the only fighter in history to win titles in eight division weight classes.
He is finishing off his 26-year boxing career with 72 fights and a record of 62 wins, eight losses and two draws.
"God is good all the time," Pacquiao proclaimed in the video. "I give all glory to God. I always believe that in God, all things are possible."
"Without Him, I am nothing," he added. "He is the one who gave me the ability to train and accomplish all those things. The Lord gave me overflowing [of] blessings."
Pacquiao thanked his family for their "unconditional love" and many others whom he said provided guidance and direction throughout his career. He gave recognition to his training team, his former promoter, the media and his supporters.
"For everyone on team Pacquiao, thank you for sticking with me through the years," he expressed. "For boxing fans all over the world, thank you very much. I deeply appreciate your love and support. Thank you for always praying for me and watching my fights through the years."
"You're one of my inspirations to keep focus and stand firm in the faith," he continued in another sentiment made towards his family — whom he said served as a constant encouragement as he pursued the competitive vocation.
Pacquiao said his decision to enter retirement from the sport did not come without difficulty as retirement will be hard to accept because he never thought the day would come.
"Goodbye boxing," he announced. "As I hang up my boxing gloves, I would like to thank the whole world for supporting me."
Pacquiao said boxing gave him opportunities he would never have imagined.
When his family was "desperate," he said his boxing career gave them the chance to fight their way out of poverty. He said boxing increased his courage, gave him hope and a platform to inspire and change the lives of others.
"I will never forget what I have done and accomplished in my life," he concluded. "I just heard the final bell. God is good all the time."
In another Instagram post on August 25, Pacquiao expressed gratitude and credited God for always being with him and for providing him with strength.
"I have come to this point in my career by the grace of God," he wrote. "It is He who gave me the strength to fight. I can look back and honestly say that I gave my best. … God bless everyone."
In addition to his boxing career, Pacquiao has pursued his political ambitions, becoming a member of the Philippines House of Representatives in 2010. In 2016, the boxer ran for the Philippines Senate and won. Earlier this month, Pacquiao announced his intention to run in the 2022 Philippines presidential election.
"Today, I boldly accept the challenge of running as PRESIDENT of the Republic of the Philippines, with a message to those who are taking advantage of the Filipino people: YOUR TIME IS UP!" the now-retired boxer wrote on Instagram.
"We need to win against poverty. … We need [the] government to serve our people with integrity, compassion and transparency. The time is now. We are ready to rise to the challenge of leadership," he continued in his written declaration. "It is time for the oppressed to win. It is time for our people who have fallen into poverty to recover. It is time for a clean government, where every cent will go for every Filipino."