وَإِنْ أُدْعَ لِلْجُلَّى أَكُنْ مِنْ حُمَاتِهَا
وَإِنْ يَأْتِكَ الْأَعْدَاءُ بِالْجَهْدِ أَجْهَدِ
Meaning: If I am summoned for a major crisis, I join those who defend against it; and if enemies press you with all their strength, I exert myself to the utmost as well.
Al-jullā means a great calamity, ḥumātuhā its defenders, and al-jahd strenuous exertion. The paired conditional clauses in ... akun / wa-in ... ajhadi reinforce one another: he claims not a single act of loyalty but a continuing habit of standing with his relatives under pressure.