What does it mean to ‘abide in Christ’?

Sinclair Ferguson writes:

The exhortation to “abide” has been frequently misunderstood, as though it were a special, mystical, and indefinable experience. But Jesus makes clear that it actually involves a number of concrete realities.

First, union with our Lord depends on His grace. Of course we are actively and personally united to Christ by faith (John 14:12). But faith itself is rooted in the activity of God.…