“If ye know these things, happy are ye if ye do them.” John‬ ‭13‬:‭17‬

From the main verse, one should ask- what things would cause happiness when done? He had been talking about humility and service:
“If I then, your Lord and Master, have washed your feet; ye also ought to wash one another’s feet.” John‬ ‭13‬:‭14‬ ‭
He had been talking about greatness:
“But it shall not be so among you: but whosoever will be great among you, let him be your minister; and whosoever will be chief among you, let him be your servant:” Matthew‬ ‭20‬:‭26‬-‭27‬
Any man who serves has the sure promise of happiness and is chief among brethren in the kingdom of God- let that be you. A man’s happiness is not found in things or people but in God’s word- in doing God’s word. The man who wants to be happy irrespective of where he finds himself, should express humility irrespective of where he finds himself- Luke 14:7-11

Bible reading plan: Exodus 33 and 1 Thessalonians 1