Bhagavad Gita 2.32

यदृच्छया चोपपन्नं स्वर्गद्वारमपावृतम्।सुखिनः क्षत्रियाः पार्थ लभन्ते युद्धमीदृशम्॥

yadṛcchayā copapannaṃ svargadvāramapāvṛtam |sukhinaḥ kṣatriyāḥ pārtha labhante yuddhamīdṛśam ||

Happy are the Kshatriyas, O Arjuna! who are called to fight in such a battle that comes of its own accord as an open door to heaven.

Blessed are the soldiers who find their opportunity; this opportunity has opened for thee the gates of heaven.

Our plain-language meaning of this verse is waiting for scholar review.