יַֽעַנְךָ֣ יְ֭הוָה בְּי֣וֹם צָרָ֑ה יְ֝שַׂגֶּבְךָ֗ שֵׁ֤ם ׀ אֱלֹהֵ֬י יַעֲקֹֽב׃
願永恆者在患難的日子應允你；願雅各之上帝的名高舉你。
Rashi
May the Lord answer you on a day of distress This psalm was [composed] because he [David] would send Joab and all Israel to war, and he would stand in Jerusalem and pray for them, as the matter is stated (in II Sam. 18:3): “It is better that you be for us from the city as aid.” Were it not for David, Joab would not have succeeded in battle.
Rashi
the name of the God of Jacob Who promised him [Jacob] when he went to Haran and kept His promise; therefore, it is stated: “the God of Jacob.”