Psalms 89:50 Halakhah

אַיֵּ֤ה ׀ חֲסָדֶ֖יךָ הָרִאשֹׁנִ֥ים ׀ אֲדֹנָ֑י נִשְׁבַּ֥עְתָּ לְ֝דָוִ֗ד בֶּאֱמוּנָתֶֽךָ׃

Where are Thy former mercies, O Lord, Which Thou didst swear unto David in Thy faithfulness?

Read halakhic rulings (Jewish law) on Psalms 89:50: and classical halakhic sources.