18 that thou mayest not appear to men fasting, but to thy Father who 'is' in secret, and thy Father, who is seeing in secret, shall reward thee manifestly.
Religious fasting is a duty required of the disciples of Christ, but it is not so much a duty itself, as a means to dispose us for other duties. Fasting is the humbling of the soul, Psalm 35:13; that is the inside of the duty; let that, therefore, be thy principal care, and as to the outside of it, covet not to let it be seen. God sees in secret, and will reward openly.
Matthew Henry's Commentary on Matthew 6:18
Commentary on Matthew 6:16-18
(Read Matthew 6:16-18)
Religious fasting is a duty required of the disciples of Christ, but it is not so much a duty itself, as a means to dispose us for other duties. Fasting is the humbling of the soul, Psalm 35:13; that is the inside of the duty; let that, therefore, be thy principal care, and as to the outside of it, covet not to let it be seen. God sees in secret, and will reward openly.