These two terms sound different but both of them share a common goal i.e. to attract different people from different areas and convert them to customers, ultimately generating revenue.
Sales are basically when you are into a face to face conversation with a customer and convincing him/her to buy a particular product.
Marketing is a prior step in sales and is the planning of sales. Marketing identifies what customer wants, what to make and what the competitors are lacking.
Marketing also is whole about how to distinguish a product from all other products in the market.
Strong sales techniques are a vital part of of of business growth and revenue. But you won't be having sales without any effective Marketing plan. The balance b/w both requires a strategy that smoothly guide leaders towards becoming a customer.
So here comes a great point to discuss, what is more important sales or marketing? In my opinion, sales need to be focused on now as you can't run your company if your sales team is focused on bringing today's business but on the contrary, you can also not ask your sale's leader to develop a plan of about next 10-15 months without losing focus on today's revenue.
Even if your sales leader is really good at future-focused strategies and trying to make it happen, they would be a marketing person and not a now-focused salesperson.