It is narrated from Sayyiduna Ubadah bin al-Samit (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Strive (perform jihad) in the way of Allah, for striving in the way of Allah is one of the gates of Paradise, through which Allah Almighty delivers from worry and grief."
Ahmad recorded it, and al-Tabarani recorded it in al-Mu'jam al-Kabir and al-Mu'jam al-Awsat as a longer narration than this. In one of the chains of Ahmad and others, the narrators are thiqat (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الجهاد / 9409
Hadith Gradingمحدثین:إسنادہ صحیح
Hadith Takhrij«اخرجه احمد فى المسند (314/5) ، أخرجه مسند أحمد برقم: 22172»