If a person has marriage written in his/her destiny, does it make sense for that person to make effort and find the right person to marry? Or can the person sit back and let destiny play its role to unite the two people when the time is right?
18.61 O Arjuna, the Lord resides in the region of the heart of all creatures, revolving through Maya all the creatures (as though) mounted on a machine!
So whether a person will make effort or sit back is also decided by God, Whom we also name 'destiny'.
According to Sri Ramakrishna-Kathamrita
The birth, the death and the marriage--all happen by the will of God.