Psalms 20:7
עַתָּה יָדַעְתִּי כִּי הוֹשִׁיעַ ה’ מְשִׁיחוֹ יַעֲנֵהוּ מִשְּׁמֵי קָדְשׁוֹ בִּגְבֻרוֹת יֵשַׁע יְמִינוֹ
Now I know that Hashem has saved His anointed one; He will answer him from His holy heaven with the mighty acts of His saving right hand.
Psalm 20 is recited after the second Ashrei in the morning service. Rashi explains this verse as follows: King David, the author of Psalms, is saying that since G-d saved him by making his army victorious over the rebellion (in II Samuel 18), David knows that G-d still desires him as king and will continue to assist him.