Islam is a community based religion. There is a heavy emphasis on congregational worship and spending time with community. When one goes to the masjid for salah, they automatically get acquainted with community members which creates unity.
We see that the masjids start overflowing in Ramadan when people flock for taraweeh, but the rest of year, masjids aren’t nearly as full unfortunately. This is despite the fact that Isha takes precedent over taraweeh which is voluntary prayer. It makes a huge difference to begin the day at the masjid and to end it at the masjid.
For motivation, here are some hadith of the Prophet (saw) that show the importance of praying Fajr and Isha at the masjid:
Uthman ibn Affan (ra) reported: I heard the Messenger of Allah (saw) saying: “One who performs Isha prayer in congregation, is as if he has performed Salat for half of the night. And one who performs the Fajr prayer in congregation, is as if he has performed Salat the whole night.”
Sahih al-Muslim and At-Tirmidhi
These hadith tell us that the reward of praying Isha and Fajr prayers in congregation is so great that it equals the worship of the whole night.’
To put it into perspective, every day you can earn this HUGE reward by just praying at the masjid. Also, it’s important to remember that consistent good deeds like this are especially beloved to Allah (swt).