One of the principles of our faith is to believe in Moshiach — and not only to believe in Moshiach, but to anticipate his coming every single day. It is a fundamental tenet of Yiddishkeit, and there are numerous references to Moshiach’s coming in the Torah. Indeed, we pray many times a day for his coming.
One of the first questions asked of each departed soul by the Heavenly tribunal is: “Have you yearned for the Redemption?” Some poskim say that believing that Hashem will redeem us through the coming of Moshiach is actually part of the principle of Anochi Hashem Elokecha, believing in Hashem.
A person who does not do so is denying a basic tenet of Yiddishkeit; therefore, it is crucial to make everyone aware of this basic principle of our faith. Part of believing in and awaiting Moshiach is not to make any pre-conditions for his coming: for example, we may not say that because Eliyahu HaNavihas not come, therefore Moshiach cannot come yet. Nor may we set a ketz (a specific time) by when Moshiach should come, but rather we should constantly be anticipating his arrival.
It is a halachah to yearn and pray for Moshiach every time we think or talk about him.