What is meant by His saying, the Most High: "So when they have purified themselves, then come to them from where Allah has commanded you," and where was the command to specify the place of coming to women mentioned, and what is the point of comparison between this verse and His saying, the Most High: "Your women are a tilth for you, so come to your tilth however you wish"?

The first verse (And they ask you about menstruation...) shows that menstruation is a harm (adha), and it commands to avoid women in the private parts during menstruation. So, if the bleeding stops and the woman purifies herself, it is permissible to approach them in the private parts, which is the meaning of "So approach them from where Allah has commanded you," meaning the place that was commanded to be avoided, which is the front private part (al-qubul).

The second verse (Your women are a cultivated field for you...) shows that intercourse is permissible in the place of cultivation (the front private part) in any posture or manner, such as approaching from behind or in front. This indicates that the permissibility is specific to the private parts, because it is the place where offspring are sown. As for anal intercourse, it is forbidden.

There is no contradiction between the two verses. The first verse specifies the place of intercourse, which is the private parts, and prohibits it during menstruation. The second verse specifies the manner of intercourse in the private parts.