Mathew.6:16-18
God is not a sadist, He's never against enjoyment and pleasure (1Timothy 6:17). But as we see in the scriptures, we see instances of God instructing us in sobriety and carrying our crosses (Luke9:23; 2 Timothy 2:3-4). God commands us to endure hardship not because He delights in our suffering but that some things cannot happen to us when we do not abstain from certain things, and fasting or abstinence is a major form of denial.
Abstinence means to refrain from something that gives you pleasure. It is not only what you enjoy that gives you an advantage, sometimes it could be something you have to endure. In 1 Corinthians 7:5, couples are advised to abstain from sex, which is fasting, and also serves as a means of denying themselves from natural pleasure.
Fasting is abstaining from pleasure for the purpose of spiritual development, fervency and prioritisation. A sad countenance when fasting is a sign of hypocrisy, rather, you put on a bright countenance as the Bible has instructed in Matthew 6:16-18.
The Advantage That Fasting/Abstinence Gives:
(1). It helps you to experience the corporate blessing of the group you belong to (Esther 4:16; Jonah 3:4-10). You cannot get corporate blessing when you disqualify yourself from corporate instructions.
(2). It is a way of keeping fit and enforcing self control. Self control is a fruit of the spirit, and one of the ways you know a spiritual person is how well they exercise self control (1Corinthians 9:24-27). If you're going to be a master at something, you must practise self control.
(3). Fasting is a way to channel your soul to spiritual things and not carnal things.
(4). Fasting clears your soul and removes the hindrance of clear communication. How you shut down noises is by abstaining from it.
(5). Fasting is a statement of honor and value for God.
(6). Fasting gives fervency to prayer. The power of prayer cannot be felt until you pray fervently, and this is done by adding abstinence in fasting.