James 5:8

‘You also be patient. Establish your hearts, for the coming of the Lord is at hand.'

So they are to await the Lord's coming with patient endurance, and establish their hearts through prayer (James 1:5; James 5:13), through the reading and hearing of the word (James 1:21; Colossians 3:16; 2 Timothy 1:13; 1 Peter 2:2), through doing good (James 1:22 and often; Hebrews 10:22) and through looking constantly to Him (Hebrews 12:1), so that they would be spiritually strong and enduring. There can be little doubt here that ‘the Lord' here signifies ‘the Lord, Jesus Christ' (James 1:1; James 2:1). It was for His coming that men were told particularly to wait.

Note the requirement to ‘establish your hearts'. Waiting for the Lord's coming requires not just patience but preparation. Compare Luke 12:35).