When the Prophet (peace be upon him) started to openly call others to Islam, and the elders of Quraysh tried to overcome him and his Companions, the Prophet (peace be upon him) started to look for a house which was far from the eyes of the polytheists and where they used to sit. This was in order for the Muslims to gather in secret for the Prophet (peace be upon him) to teach them Islamic rules, recite ayahs from Allah, the Most Merciful, to them, purify them and teach them the Book and the sunnah (ways) of the Prophet (peace be upon him). Therefore, the Prophet (peace be upon him) chose Dar Al-Arqam. There was no doubt that if the Prophet gathered the Muslim together in front of all the people, the polytheists would try to harm him and the Muslims with him to prevent them from Allah’s path. This gathering in the open could also result in the two groups coming into conflict. Secrecy was a wiser course of action at this stage.
But with regards to the Prophet (peace be upon him), he used to openly call others to Islam and worship Allah (Glorified is He) in front of the polytheists. The Prophet (peace be upon him) did not hide any of this. However, he used to have meetings with the Muslims in secret for the benefit of the Companions and the call [The Prophet’s Biography by Ibn Hesham].