Best Wishes on Retirement of Colleague –
[Name, Company Name & Address here]
It was good news to know that you are finally retiring after so many years in work.
You had a successful career with this company, and contributed so much to this organization and its people. Now, you really need time to enjoy with your family members
I wish you and [Spouse name] all the best for future.
You can finally explore your areas of interests as you have enough time ahead.
P.S. – Will I get to see you playing golf everyday?