Albert Barnes Commentary Mark 11:25

"And whensoever ye stand praying, forgive, if ye have aught against any one; that your Father also who is in heaven may forgive you your trespasses." — Mark 11:25 (ASV)

And when ye stand praying. When you pray, it seems that the posture in prayer was sometimes standing and sometimes kneeling.

God looks upon the heart rather than upon our position in worship; and if the heart is right, any posture may be proper.

It cannot be doubted, however, that in private, in the family, and wherever it can be conveniently done, the kneeling posture is more proper, as expressing more humility and reverence, and more in accordance with Scripture examples (2 Chronicles 6:13; Daniel 6:10; Luke 22:41; Acts 7:60; Acts 9:40).

Yet, a subject like this may be given too much importance, and we should be careful that anxiety about a mere form should not exclude anxiety about a far more important matter—the state of the soul.

Forgive, etc. See Barnes on Matthew 6:12, 15.