What is the ruling on buying shirts and cups with da'wah and preaching phrases printed on them with the intention of da'wah?

It is permissible to write religious phrases and verses on objects and purchase them if the intention behind it is legitimate, such as raising the banner of Islam and inviting people to it, and provided that it does not lead to the degradation of Allah's names or verses. This is supported by the action of Umar ibn Abd al-Aziz, as horses used to go out with "عدة الله" (Allah's preparation) written on their thighs, and by the permissibility of writing "Allah" on charity camels for blessings. However, if it involves degrading Allah's names and verses, then it is not permissible.